“When people say ‘larger than life’ I don’t know what they mean,” says James Corden, cackling. “It’s not just men in the street who say that. It’s journalists. When I ask them, they are never able to explain.”

Well, this organ would never stoop to such a threadbare cliché. Still, I think I have some idea what the phrase means and have some understanding why it has been applied to Corden. He booms. He chortles. It requires only the slightest prod to trigger a (capitals required here, I think) Theatrical Anecdote concerning his adventures on the set of Into the Woods, in which Meryl Streep appears as an archetypal Grimm witch in the glossy take on Stephen Sondheim's immortal musical.

“My great moment was managing to convince a section of the crew that Meryl had been fired,” Corden says, describing a conversation with co-star Anna Kendrick. “Two heads of department were having a heated conversation. Anna asked what that was about and I said: ‘Haven’t you heard? Meryl’s been fired.’ She was like: ‘Oh, shut up.’ ”

Corden knows how to build such a yarn. He then has Christine Baranski, who plays Cinderella’s Godmother in this musical deconstruction of fairy tales, approach and silently absorb a sly wink from the prankster.

“She topped it off with a line that I’ll never forget: ‘Glenn Close is already on a private jet.’ Ha ha ha.”

The Corden cackle is so infectious and his delight so unforced that it proves impossible not to be swept along in the conspiracy. You see? This is what they meant by “larger than life”.

OBE man

We speak a week or so before news emerges of Corden's OBE, but he has been surfing a precipitous curve for some time. It is a decade since, already in his mid-20s, he registered as one of the schoolboys in the Royal National Theatre's production of Alan Bennett's The History Boys.

Raised in the western reaches of greater London, Corden, who had been acting since his teenage years, rapidly became inescapable. His charming sitcom Gavin & Stacey – in which he played harmless Smithy from Billericay – ran successfully from 2007 until 2010. He collaborated with Dizzee Rascal on England's 2010 World Cup song.

There were significant missteps – iffy sketch show Horne & Corden and dire movie Lesbian Vampire Killers stand out – but Corden soon demonstrated the most useful of all showbusiness traits: the ability to bounce back stronger than before. The National's production of Richard Bean's One Man, Two Guvnors toured the world and eventually earned Corden a Tony award.

A tale of two actors

After all that, the recent OBE seems like a meagre reward.

“My theory is that there are only two types of actor, both as good as the other,” he ponders apropos of nothing obvious. “There are aliens and there are humans. The aliens are people you look at and think, how does he do that? People like Daniel Day-Lewis and Ralph Fiennes. Benedict Cumberbatch is like that. Mark Rylance would be another. Then there are other actors who, whatever they’re playing, will be representing us, the audience. Neither is better than the other.”

The point, I imagine, is that Corden falls into the latter camp. That makes sense. A man of everyday shape, with a flexible face and a rather sweet voice, he is certainly not among the heroic caste of actors. But then neither was Charles Laughton. Neither is Timothy Spall. Corden is likely to remain the character tasked to represent the hopes and fears of the ordinary man.

One possible downside to such an image – bolstered by amiable performances on chat shows – is that members of the public might mistake him for their best mate. You wouldn’t fling your arm around Derek Jacobi or (even when alive) Paul Scofield. Would you?

"I don't know. I am often quite a happy person," he says. "You will always have a better day if you Google Earth yourself and see how irrelevant your problems are. The biggest thing is that people think I am Smithy from Gavin & Stacey. I have never even been to Billericay.

“I don’t go out that much. You get this weird thing where people buy you pints. And I don’t enjoy lager. I don’t like the taste or experience. ‘There you are, mate. Get that down you.’ I do say thanks. But I’d prefer sparkling water with some fresh lime.”

A date with the Late Late

At any rate, Corden's perceived amiability has just helped him make one more giant leap up the ladder. There was much surprise when, a few months ago, it was announced that he would to take over from Craig Ferguson as host of CBS's The Late Late Show. Where the hell did that come from? It transpires that he's as surprised as anybody else.

“I wish I knew. I wish I had an idea of how it’s landed on my lap,” he says with aggressive wags of the head. “Leslie Moonves, the chairman of CBS, and Nina Tassler, who’s the president, came to see me in the play and they really enjoyed it. They asked me to write a sitcom and as I started to write it I realised that this wasn’t a network show.

"I was hours away from signing an HBO deal when I was called in to meet them. We were just chatting about TV. Craig had just stepped down. I really didn't realise that I was being interviewed. When I left, my phone rang and they said they wanted me to host The Late Late Show."

If Corden is merely pretending to be astonished, then he really is worthy of that Tony. With only a few months to go before he takes over the show, he genuinely seems to be having trouble processing the information.

"I feel a bit like someone tapped me on the shoulder and said: 'You've joined the Sky Tour de France team.' Erm, you know I don't do that? What I adore is acting. But, when I looked at it, the pros far outweighed the cons."

Among the pros is the fact that, rather than zipping about the world, he will now have a job that anchors him to Los Angeles, where he now lives with his wife, Julia Carey, and their two young children.

“Yeah, I want to be there for my family,” he says. “I don’t know much about being a parent, but very few children sit in therapy saying: ‘My parent were just around too much. They just loved me too much. I just had too many cuddles from my dad. That really hurt.’ I am going into this with eyes wide open. I am sure it will be a disaster, but I do what I do.”

By happy coincidence, his part in Into the Woods – a baker who avails of a witch's assistance to make his wife pregnant – is perfectly tuned for a new father. It is the baker who helps articulates Sondheim's theory that fairy tales reveal the unhappy truths about the universe to children.

“Yes. That’s right. What we’re saying is: whether you like it or not there are some screw-ups coming your way and there’s nothing you can do about it. That’s just life.”

And there is no point fearing opportunities like, well, hosting a major American network chat show.

“Hey, if it doesn’t work out then it doesn’t. I am a 16-stone guy from High Wycombe. What part of you thought any of this would work?”

Into the Woods opens today