Outside Television City in Los Angeles – the CBS building – here’s a giant billboard of James Corden smilingly promoting the Late Late Show, which has been one of the most runaway successes a television host has ever had. He inherited the show when it was bottom of the rung for guests and viewers alike. Now The Late Late Show’s You Tube channel has over 2.6 billion viewers and after his first year the show was nominated for 4 Emmy Awards in 2016. Once inside he reminds me that he’d been working at CBS for nine months and the show had been on air for several weeks and he still had to show ID to get into the building.  Not any more. In 2015 he was knocking on publicists doors hopeful to get someone to sit on the sofa and he could only dream that proper stars could do Carpool karaoke with him. A year later he’s driving around the grounds of the White House with Michelle Obama and Missy Elliot singing Get Your Freak On.

I’m here to watch the show, which is fast paced, high energy and filled with joy.  The guests were Diane Lane, Benicio del Toro and Michael Fassbender.  And a new Carpool Karaoke with Harry Styles was premiered. I’ve sat in taped talk shows many times. They’re usually boring with sound bites edited and re-taped, mistakes etched out and filmed over. Not here. It’s a continued burst of infectious jaw aching laughter and pace with the odd self-deprecation where he’ll say things like he thinks he’s thin until he watches the show back. But more of that later.

Afterwards in the green room I tell him his show was great and he seems genuinely touched, modest to a fault. He’s bringing the show to London June 6-9^th He’s more anxious than excited about it.  The UK loved him as a Fat Friend (he co-wrote wrote with Ruth Jones of Gavin and Stacey fame) and in Gavin and Stacey but then he became scrutinised. He could do no wrong and then he could do no right. He was called arrogant. His sketch show with Matthew Horne was panned yet on stage in One Man, Two Guvnors he enthralled. He took it to Broadway in 2012 and this in many ways set him up to become the talk show that he is – part musical theatre performer, part television actor, part existential joy. The guests all love him. He manages to be funny without being cruel. A rare gift.

The next morning I see him on the rooftop of the CBS building. He’s mid shoot and pretending to eat a chip from a newspaper wrapping. Quintessentially English but not necessarily quintessentially Corden. He tries to be good about the chips and he’s already done an hour in the gym. Once we’re ensconced in his office he abandons his desk in favour of a cosy sofa and comforting green juice. He shrugs, “I try.”

The office outside is filled with rails of suits and shoeboxes from Prada and Paul Smith. In one of the boxes is an award from Victoria’s Secret. TV’s sexiest host. He blushes pink and shuts the box tight.

With Corden there’s no interview tightrope walking. There’s no awkward moments. There’s no warm up. He’s very much as he is on TV. Always on always present, always to the max. Producers and assistants weave in and out to ask questions about the London shows. He asks them if he can tell me who the guests are or anything about it. They tell him no and he obeys.

Is he excited to return to the UK with a super successful show? “I feel more anxious than excited. Shows have gone across America but taking it to the UK brings a lot of technical problems.  What does the stage look like? How do we build the set? How do we afford it?”

Is he also anxious that the Brits may not embrace him in the same way as the Americans? You see him thinking as if it’s the first time it’s occurred to him but he’s used to people embracing him and then not embracing him.  “I guess, maybe but not really.  I think we have to be mindful that we are making a show or a predominantly American audience but it airs in 150 countries so were just going to make it as exciting as we can.”

So the guests that you’re not going to reveal. Do you choose people that you love or people that you already know? (he always seems to get on intimately with the occupants of his sofa). “I never know who they’re going to be till they’re here at the show. Most people are lovely and the environment of our show is warm and we just create organic conversations as much as you can.”

Of course nothing was organic as the start of his because American publicists did not want their clients to share a sofa with other guests. They were used to the traditional talk show format with guests coming on separately. “That’s where Graham Norton’s show was unbelievably useful.  We couldn’t book anyone for a long time.  The show traditionally had not been a slot with the widest of audience and after driving around to publicist’s offices they would often say my clients don’t sit with anyone else and I would say but they already did a year ago on Graham Norton. So we were starting below zero and that can be incredibly daunting. But what you have to do is take in all of the negative and make them plus points and people love an element of discovery. And as much as I was painfully aware of how unknown I was here, I had done my 10,000 hours.”

Malcolm Gladwell said you had to have done 10,000 hours of something to be good at it in his book The Story of Success and now in a total of 2 years, on You Tube alone, 2.6 billion You Tube views and ten million subscribers making it the fastest growing subscription channel in history. “It’s lovely,” he beams. There’s a padded heart on his shirt which seems a perfect metaphor. He’s wearing his heart on the outside and he’s not afraid to show the love. People feel at ease with him which is why Carpool Karaoke – the guests and James sing as they drive around in a car – works so well.

“There’s a humanising environment.” Oddly Mariah Carey was the first Carpool Karaoke of the Late Late Show although the idea had been premiered with George Michael back in 2011 and Gary Barlow for Comic Relief in 2017. Was he nervous? “Not really because I knew it was a good idea but in many ways I’m always nervous. I’m a fan of nerve. Nerves are good because if you’re nervous of something it matters. You want to do your best.   Like when we did One Man, Two Guvnors I remember so vividly the first preview of that show at the National Theatre. I wasn’t onstage for the first seven or eight minutes and I’d wait behind this door. The most nerve-wracking moments of my career have been behind that door and the day before this show started airing and I was behind the curtain and you know there’s a moment where you’re going out on the stage you have to enjoy nerves.

Does he fear being judged? “Of course, everybody does.” You’re only ever setting out to do something that’s your best. No-one sets out to do something bad.  You just want any criticism to be fair.” His eyes look a little distant. A little pained. Ever such a little.  Perhaps because there was a tine I the UK where criticism was heaped upon him. Was that one of expected? Was it one of those we’ll build you up to knock you down? Themes? He wasn’t allowed to stay on a Gavin and Stacey high forever. He nods. “It got out of proportion perhaps but the fundamental ting was the work I was doing wasn’t good enough. The sketch show (with Matthew Horne) wasn’t good enough. I hosted the Brits not well enough and then the film came out called the Lesbian Vampire Killers and it was awful. Really bad. But in many respects I’m thankful to it because it makes you realign yourself and think this is a serious thing and you’ve got to take your work seriously. The only time I got obsessed by it was the only time I felt there was an enjoyment I the bashing.”

I’d meant to warm up to this moment. I hadn’t meant for this difficult stuff to come so early in our conversation but he doesn’t mind. “Also something has changed in the retelling of this that somehow my career was over. I was responsible for the film, the Brits and the show that wasn’t good enough but it wasn’t like my career was over. At the very point that all these things were happening I was writing series 3 of Gavin and Stacey the most anticipated comedy of the year. So if that’s my low point I’ll take it.”

The shows finale which went out on New Year Day 2010 had an audience of 10 million and considering the show started off on the scarcely watched BBC3 this was an absolute milestone.  Does he feel he’s more appreciated in the US because Americans like a warmer tone and maybe the British humour is crueller? “No. Victoria Wood was warm, French and Saunders were quite warm. I don’t subscribe to that notion. “I don’t have any interest in making people feel uncomfortable. It’s not enjoyable to be constantly elevating yourself as a superior being which is what it is when you’re mocking someone or something. It can be funny once or twice but it’s a sure-fire way to get your show cancelled if you have one note and one tone. You have to keep changing it up and making it interesting for people.

I think the biggest difference is America doesn’t have a national press. It’s harder to get a momentum going…” The Corden bashing seems to him “a long, long time ago. It was before I met my wife about 8 years ago.”

This co-incides with a period where he seemed to be looking for love at all the wrong parties. He was on/off with Sheridan Smith then he met his wife Julia who worked for Save the Children and has been described as ‘a hot Mother Theresa’. He chuckles, “That wasn’t my line. That was Ben. Ben Winston my best man (and producer at CBS). It feels like another lifetime. Then I did a series called The Wrong Mans which I’m very proud of the I was in Into the woods and then I moved to America and launched this show. I’ve had my ratio of hits to misses. I hope I’m on the right side of hits. The misses had zero impact on my career. I never felt I came here and had to start again. I just carried on. Some people wrote things which weren’t very nice but you carry on. I think there’s a fine line between confidence and arrogance and I would say I haven’t always trodden that line properly. I can understand why people might think I’m arrogant but I also don’t think it’s true.  I do have a sort of confidence if you like which can be perceived as something different. I don’t even know if that’s true. I think you can’t sum up the people of Britain buy what a few journalists have said. You can find something bad in anybody.”

And as Corden well knows, you can also find something good in anyone or any situation. “Part of the reason we want to take this show home is we felt a huge and overwhelming sense of positivity from the UK.  To appear on Carpool Karaoke you can’t take yourself seriously, yet Corden has had Adele, Michelle Obama, Stevie Wonder (driving) Madonna, One Direction, Katy Perry. Harry Styles, Red Hot Chili Peppers and Justin Bieber singing live with Corden, all of which have gone global. He has introduced a new audience to the show so they feel invested in its newfound success. Carpool Karaoke has had a zillion Facebook shares which means there’s a genuine anticipation for his return to the UK.  And I think he returns to feel the love.

Corden was born in August 1978 (38) in High Wycombe, the only boy with two sisters. His father was a musician in the Royal Air Force and is now a Christian bookseller. Corden seems remarkably well adjusted. His childhood was nothing like Oranges Are Not the Only Fruit but when he grew up both of his parents were in the Salvation Army. “Being in the Salvation Army was a huge part of our life until our parents realised that the particular Salvation Army we went to was full of the least Christian people you could ever meet. They were people who just wanted to wear a uniform.”

His mum and dad had the uniform but he left before it got to the stage of him wearing gone. “Maybe all churches are strange organisations because religion is one thing and people are another.” Is he still a Christian? “I don’t know…” There’s a pause while we shuffle cushions around on his couch. “I struggle with it sometimes. I am not one to question science. Science is great but at the same time if you’re growing up in a house but have the overwhelming feeling that all of this can’t be for nothing, it means you don’t know.  I don’t think it’s as cut and dried as heaven and hell but I hope there’s something else.”

Now a few years back when he was going through a bad time his mum and dad came round and his dad said, “We should all pray,” and they did. He found it comforting. “It was essentially my parents saying ‘you’re not on your own now. We’re here.’ And it’s incredibly moving when you spend any of those moments with your parents. I feel very fortunate that I’ve always had supportive parents… they pop up in the show and I’m sure they’ll be in London every night. My dad will be playing in the band.” (He plays saxophone, clarinet and flute).

They were in the audience at the Grammy’s and possibly will be again next year when he hosts the 7^0th Grammy’s in Madison Square Garden. This ear he’s not doing the Tony’s. “I felt I might have a little too much on my plate but the Tony’s is one of the best nights of my career.”

He was really at home on stage there. He knew everybody who was winning and losing. “It was an unbelievably supportive room.”

I’m not sure if it’s thinking of his recent trip to New York on the red eye and back again the next day but he yawns. I yawn. Why is yawning contagious? “It’s weird isn’t it? Also why can’t you tickle yourself?” we laugh.  It’s a very good thing laughing is contagious. “We bank on that on our shows. Last night he’d had a drink with Michael Fassbender and Benicio del Toro while Harry Styles was rehearsing. “It was lovely,” he smiles “And Harry. I’m very proud of him. I believed in all of those boys.”

At one point Styles moved in with the show’s producer Ben Winston who was like a godfather mentor figure. Did he ever have a mentor? “There have been people who have been unbelievably influential. Shane Meadows who cast me in a film called 24/7, a boxing movie with Bob Hoskins. He was 24 at the time. If you’re 17/18 working with a director who’s 24 you think oh, you don’t have to wait to do anything. You can just do it. He was an incredibly influential person in my life and the other one is theatre director Nick Hytner. I’ve worked with him twice in the History Boys and One Man Two Guvnors and these were both incredibly formative points in my life. I remember when I watched the first cut of the first ep of Gavin and Stacey. I was incredibly down and called him and he said are there three moments that you think are good enough and I said yes. I suppose so. And he said if you think there’s three there’s at least 10. It’s a bit like if you watch the movie of the book you wrote you’re visualising what was going on and what could never ever be but the more you live with what’s on screen the more you’ll fall in love with it.” He was completely right.”

Fortunately for Corden a lot of people fell in love with it.  Corden created Gavin and Stacey with Ruth Jones when he saw his peers, the other actors in The History Boys and his flatmate Dominic Cooper being offered roles in movies – leading roles and he would get offered the fat boy who delivers a TV to Hugh Grant. If there was no future for chubby boys as leading men he would have to create one so he and Jones created Smithy who was so loveable in Gavin and Stacey.  Does he miss acting? Being onstage? Acting on TV? His schedule is so intense it makes it almost impossible although he did do a few days shooting for a little part in Oceans 8.

He also plays Hi Five in Emoji Movie which opens this summer. It’s a big part and it’s super cute but it’s animated voiceover so it’s the kind of movie you can show up in your pyjamas and still do a great job. From doing so many TV shows he’s not only put in his ten thousand hours but his comedic timing is honed to perfection.

“I’ll be really disappointed in myself if I didn’t do another play.  I’m doing this show 4 days a week but not 4 days a week until I die.  We’ll see. We’ll burn that bridge when we get to it.”

Corden was always a natural actor and prankster. When he was about 13 “I called in Richard and Judy on This Morning and told them I was being bullied at school. I was off school on a teacher training day but my Auntie Marilyn recognised my voice and called my mum and then I had to hang up. I’m not proud of it but I guess there were worse things I could have been doing at the age of 13. I said I was Chris from Buckinghamshire or something.”

In reality he was never bullied at school. He was never the fat boy who had to make jokes to be popular, and he even says there were plus points. 2my size and shape has helped me as many times as it hasn’t and that was the very thing that made me want to write.  That’s when I started talking to Ruth Jones about Gavin and Stacey.  There were eight of us boys as History Boys, all of similar ages and points in our careers and I’d be the character who’d drop a TV off or be the newsagent and everyone else was coming in with film scripts under their arms. And I had to think I’m only being offered these parts because some people would say if you look a certain way you’re not interesting to people and your stories are not as valid as other people’s. I always felt like I’d be offered a lead in something and then it became clear that that wasn’t going to happen and that’s when I thought OK. I ‘m going to have to muscle my way in here because no one was saying come and have a seat at the big table. That’s how the writing of Gavin and Stacey came about.”

His weight has been constantly fluctuating. He’s been stones bigger than he is now and lighter. He lost a lot of weight doing Amelia Freer diet that was successful for Boy George (look up) Her book was Eat Nourish Grow. “It’s always going to be a constant battle. I went to the gym this morning and look at the green juice. I’m trying.  There’s so secret to it. It’s eating less and doing more and trying to avoid bread. That’s my biggest weakness.”

And what about drinking? “I don’t really drink very much. I’ve never been a big drinker. I’ve never been let’s get a glass of wine. There’s a delicious cocktail at the Soho House called Eastern Standard and I like them but my biggest problem is avoiding toast. My children are always eating toast. Me and my wife in bed with marmite on toast at 10.30 watching Big Little Lies.” He beams, an extraordinary ear to ear blissful beam.

He has a six year old son Max and a 2 year old daughter Carey. “There’s not a diet I haven’t done. I’m trying to be good and going to the gym and there’s a dance class I like to go to every now and then.”

Is he not too famous for a dance class open to the public? “No, clearly not. Who is too famous to do a dance class?” Harry? “No he’s not.” Katy Perry? “No. once you’re in it you’re in it. You can’t start living your life like that.”

I tell him about when I did a Pilates class with Nicole Kidman and there were 300 paparazzi’s outside the watching us leave. He enthuses about the dance class. “It’s called Plyo-Jam and it’s dance using Plyometrics. Lots of jumping and moving and sweating for 45 minutes and old fashioned fucking star jumps.”

He finishes off his green juice. Very LA. “We’re here for another few years without question unless I get fired. We’ve just bought a house and we feel very settled as a family.”  Does hot Mother Theresa Julia work? “Yes. She’s got an amazing job looking after two and a half children – me being the half.” Where and how did you meet? “Through my old flatmate Dominic Cooper. They’ve known each other for years because they grew up in Blackheath. He introduced us.”

Was it love at first sight? “It was for me. I doubt it was for her but for me she’s incredible. People always talk about me and how much work the show must be but it’s nothing compared to what she does. Our daughter was only twelve weeks old when we moved here. I had to come out earlier because my daughter didn’t have a passport. It was a massive thing to just pick up our life and come here, you know.  And we’re happy because we’re together all of the time. It’s not like I’m doing a movie where I say I’ll be back in a few months or a play with eight shows a week where every night you’re on your own. Predominantly this show is me being here in this office coming up with ideas and then we go and shoot stuff and do the show. Home every night.”

So in a way it’s more stable for them as they see more of you. “Without a question. Yes. I’m off at weekends and that’s just glorious. I watch football on TV and play with my children.” Is he a good husband? “I hope so, yes. I certainly try to be.” Was he a good boyfriend? “I hope so otherwise I don’t think she would have said yes.” What about other relationships. His on/off with Sheridan Smith. Was that fun? “Yes,” he says hesitantly. “I really don’t want to talk about other relationships in my life because I wouldn’t want to read about my wife’s ex- boyfriend. I don’t know if Sheridan has got a partner but I don’t imagine he would want to read about fun times that we had so I always try to be respectful.  We certainly dated for a while.”

Does he stay in touch? “No, no. I don’t. No.” Is that because your wife wouldn’t like it? “No. it’s because we were together, then we weren’t.” And that’s it? “Yes.” Seems very definitive. Is he like that? “I don’t know if I’m like that or not but that’s the situation. My previous girlfriend before that, Shelley, I was with for seven years. We lived together and I think there’s a reason you stop being together so then to carry on in any other way is not my thing. It’s not anything that I’ve ever thought about doing. It doesn’t mean there’s any acrimony but it’s just not part of my life.”

It seems weirdly brutal if you think about it and especially odd for a man who’s so full of warmth but it has a logic to it. Things aren’t working, no children involved. You get on and concentrate on another relationship that IS working.  Is he the same person at home as he is at work? As full on? “I try to be but sometimes the days here are a spiral of constantly talking and I get home and the last thing I want to do is talk. However my wife would have spent the day talking less so I’ve realised is wherever you are and whatever you’re doing you just try to be present in that moment right there. Like I’m trying to be as present as I can in this interview as opposed to thinking after this I’ve got to do this, I’ve got to do that. It’s the same in your home life. I try to be a present father and a present husband. It’s something you have to learn to do really.”

Does he sleep much? “Are you kidding? Last night I slept like a baby. 10 o’clock until 6am because the last two nights I was on a plane to New York and only got three hours sleep on a plane. Not fun but sometimes you’ve got to do it. You just don’t have any choice.”  He yawns again. “I could genuinely fall asleep right now but I’m not going to. I consider my job being the thing I have to care about every single second until the moment the show begins. Then all I have to care about is enjoying myself. That’s all I can do.