After a year in which he won a Bafta for playing the lovably flawed Smithy in Gavin & Stacey, then a British Comedy Award for co-writing the thing, and was extolled as the new face of British comedy, James Corden is entitled to put up his feet on Christmas Day, light a foot-long cigar and let out a long, smug sigh. Unlike poor Smithy, who, when we last saw him, was trying to come to terms with his new status as a father after Ness, played by Corden's co-writer Ruth Jones, gave birth. The story continues in a one-off - and possibly final - Christmas episode.

You've just finished the special. What's the run-up to filming like for you and co-creator Ruth Jones?

It's always quite a turbulent time for Ruth and me. We'll always fall out at some point. First and foremost, we're incredibly close friends but as you gear up towards pre-production all our conversations become about the show and technicalities. There's very rarely more than a “How are you? Great, listen, about that thing ...”

So what can we expect from the special?

It sounds silly to say it but it's really Christmassy. A lot of Christmas specials aren't any more. Our show lends itself so well to Christmas in that it's about families coming together, about finding the extraordinary in the ordinary. The excitement of Christmas Eve and Christmas morning, lunch, presents, games. We just tried to imagine what [Gavin's parents] Pam and Mick would do.

Which bits will be informed by your own family Christmases in High Wycombe?

Phrases, mostly. Something that didn't actually made the special, but which we always thought would, was the phrase “Well that's that for another year.” Which sums up Christmas in a way - my mum and Ruth's mum would always say that at about 10pm on Christmas Day.

You and Matthew Horne, who plays Smithy's best mate Gavin, estimate that you've spent 230 days together this year. Have you got on each other's wick?

We haven't so far. It helps that we're incredibly similar and yet every different. We're similar in our work ethic and the things that we love: comedy, football, social stuff. There are so many times when I know exactly what he's going to say, and vice versa. And yet we're completely different in terms of where we socialise: we will often be out at the same time but in very different parts of London. I'll be at Michael Bublé and he'll be seeing some obscure band I've never heard of. I like a melody; that doesn't seem to matter to Matt so much.

From Girls Aloud to Snow Patrol, Gavin & Stacey has always been about plausible music. Will you be wheeling out the Slade and Wizzard for the special?

I love Christmas music, I just love it. The first plan was to have Christmas music throughout, but it was like being beaten up by Christmas. So we found a great track by Albert Hammond Jr from the Strokes, which is a regular song but still sounds really Christmassy.

Why do you and Ruth have such a good feel for social minutiae?

Because we both still live in the world that we write about. Neither of us is spending Christmas by a rooftop pool in Los Angeles. I'll be with my family in Bucks and Ruth will be with her family in Wales.

Come on, your life must have changed a bit. This year you've flirted onscreen with Lily Allen, been a regular at the Groucho Club ...

As much as it may look that I'm embracing that lifestyle, it doesn't feel like that. I still live in the town where I grew up. I went out with all my old schoolmates last weekend in hideous pubs in Wycombe. None of my mates could care less.

And so to the million-dollar question: will there be a third series of Gavin & Stacey?

We really don't know. Ruth and I are executive producing an American version of the show for ABC and we're looking at some writers. It's so strange getting these CVs from people who've written some of my favourite TV shows: Arrested Development, Seinfeld, Will & Grace.

Rumour has it you'll have Gavin coming from New Jersey and Stacey from South Carolina.

I'd imagine it will be something like that, but it isn't definite yet. It's odd because we're part of it, but we have to let part of it go.

Is it true that you and Matthew are doing a chat show?

We're not - I don't know where that came from. But we are starring in a film, Lesbian Vampire Killers. which comes out in the spring, and we're doing a sketch show called Horne & Corden. We were going to call it Horne and Corden Have Come, but we didn't want anyone to be put off before they'd seen it.

And you also have a part in Richard Curtis's new film, The Boat that Rocked ...

It's the most fun I've had on a film set in my life! It's about pirate radio DJs in the Sixties, on the boats, and stars Philip Seymour Hoffman, Bill Nighy, Kenneth Branagh and Emma Thompson. I would work with Richard Curtis every day of the year. I've never known anyone create an atmosphere on a film set quite so brilliantly as he did. Put that together with a guy who really knows how to write a joke. He's something else.

Gavin & Stacey Christmas Special, Christmas Eve, BBC One, 10pm

WHO WE'D LIKE TO STAR IN THE US REMAKE

GAVIN & STACEY

Gavin is the dullest character, so how about Josh Hartnett? Or, with his resemblance to Horne, Joaquin Phoenix? If South Carolina stands in for Wales, Southern belle Ashlee Simpson could play Stacey. Or maybe another ditzy blonde with a colourful past: Paris Hilton.

SMITHY & NESS

He's tubby, slobbish, rubbish with birth control - Seth Knocked Up Rogan is a perfect fit. She's sassy, down-to-earth, fond of pies - look no further than Gossip frontwoman Beth Ditto. Or, to emphasise the Welsh-American link, perhaps Catherine Zeta-Jones in a fatsuit.

PAM & MICK

If the Shipmans relocate to New Jersey, Gavin's mum and dad must surely be played by those paragons of Noo Joisey family solidarity, Edie Falco and James Gandolfini of The Sopranos - although a less threatening pair of in-laws for Stacey might be Dustin Hoffman and Barbra Streisand in Meet the Fockers mode.

BRYN

Eugene Levy would surely make a great fist of Stacey's middle-aged, good-natured, trivia-obsessed uncle. Steve Carell has already starred in one successful UK-US transfer, the American Office. Or how about Tom Cruise, who, like Bryn, is modest of stature and harbours a penchant for fast cars and pumping iron.

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