James Corden goes Into The Woods for American adventure

James Corden has one of those infectious personalities that brighten up a room.

Today, however, he’s being more literal with his powers of illumination, playing with the dimmer switch of the London hotel suite I meet him in.

“That’s better,” says the Gavin and Stacey star before settling into the seat opposite me. It was very dark in here.”

Awarded an OBE in the New Year Honours list, James won’t have to worry about turning the lights on in the middle of the morning from next week as he’s off to a place where, according to the travel brochures, the sun always shines.

Along with wife Julia and the couple’s two young children, three-year-old son Max and two-month-old daughter Carey, James is off to live in California where he will be replacing Craig Ferguson as host of iconic CBS talk show The Late Late Show.

“It’s completely ludicrous,” says James of his future employment. “I feel the same way in my stomach as I would if someone came up to me and said: ‘So, James, you’re our pick to ride for the Tour de France team next year.’

“I couldn’t be more sight unseen over there so to go from that to sitting down chatting to America every night, it’s completely unfathomable.”

How long he will be leaving us for will largely be decided by the reception he receives from American viewers. Scotsman Craig did a 10-year stint before announcing he would be stepping down earlier this year. James would be happy with 10 months.

“My wife was like, ‘Should we buy a house in Los Angeles?’ And I said, ‘Absolutely not. We will get somewhere on a month-to-month lease,’” the 36-year-old laughs.

“Because if it’s on the network in 12 months’ time, that will have exceeded all my expectations for it.”

James is leaving us with Into The Woods, a film adaptation of the Stephen Sondheim musical which brings together some classic fairy tales and gives them a twist.

The Londoner plays The Baker, who is tasked by a wicked witch (the marvellous Meryl Streep) to bring her Cinderella’s golden shoe, Red Riding Hood’s cloak, a lock of Rapunzel’s hair and Jack’s milky white cow in order to lift a curse on his house that prevents him from having children.

A smile lights up James’s face when the subject of fatherhood comes up, having welcomed his daughter into the world just a short while ago.

“Don’t get me wrong, it’s really hard,” he cautions. “A friend of mine told me beforehand that having one is like you’ve got a nice pet, two is like you’ve bought a zoo!”

It’s James himself who has done the growing up since I first met him as one of the young stars of Alan Bennett’s stage play The History Boys.

A larger-than-life character, his over-confidence had a habit of rubbing people up the wrong way. He fell out with long-time comedy partner Mat Horne after their failed BBC2 sketch show and was publicly admonished on stage by Sir Patrick Stewart for the tone of his jokes at a 2010 awards ceremony.

Corden admits he was “struggling” at the time with finding himself single for the first time.

He had been in a nine-year relationship that finished in 2007, and his Gavin and Stacey co-star Sheridan Smith ended their “turbulent” affair two years later.

James was living in a north London flat with his History Boys mate Dominic Cooper enjoying a partying lifestyle he thought he had missed out on by becoming an actor instead of going to university.

“I don’t remember a time when I didn’t want to perform. There was never anything else, no Plan B.

“That’s why I was always forming boy bands and appearing in school plays, any outlet to perform really. But I don’t think anyone can prepare themselves for fame.”

But after being part of his early success and then encouraging his excesses, it was Cooper who saved him, introducing him to television producer turned charity worker Julia.

Smitten instantly, the pair got engaged on Christmas Day 2010 and Julia gave birth to their son three months later.

Now quietly spoken and endearingly polite, James is a changed man and a pleasure to meet. He parts with some sage advice for youngsters.

“If there’s one thing I wish I could go and tell kids today it’s that the best and richest and most brilliant people in the world really were not the most popular or best looking people at school.

“The kids that think they’re really cool are going to stay in the same town and probably become estate agents. It’s all the geeks and nerds that go off and do the brilliant stuff.”

And following his festive success with Into The Woods and his move to America on the horizon for 2015, settled James is now happy to be regarded as a nerd doing brilliant stuff.

Into The Woods is in cinemas on Friday.