I'm not entirely sure how to describe Simon Pegg's new film, Hot Fuzz. The heroes are a pair of British coppers, the setting is the Somerset town of Wells, and the finale features a bloodbath in the market square in which a host of Great British character actors are dispatched in very Great British ways: decapitated by hanging baskets, garrotted by brass knick-knacks, splatted by beer barrels, gunned down by the Somerfield's meat counter.

It's also that rarest of very rare things: a British film that's actually funny. 'How would you describe it?' I ask him.

'Lethal Weapon meets Miss Marple,' he says. 'Or The Bill, but as directed by Tony Scott.' Which is also more or less how I'd describe Simon Pegg. Except instead of Miss Marple he'd be the bloke from some Channel 4 sitcom, and instead of Lethal Weapon, it'd be Mission: Impossible

If that sounds preposterous - and the charm of Hot Fuzz and its central conceit is the absurdity of crossing a Hollywood action movie with a West Country setting - you'd be right. But it does almost exactly describe Pegg too. Born in Gloucester, he was in Spaced - a Channel 4 sitcom he co-wrote with Jessica Stevenson - and last year he did appear in Mission: Impossible III. He must surely be the only actor alive who's played opposite both Lynda Bellingham - in the ITV sitcom Faith in the Future - and Tom Cruise.

They're both - Hot Fuzz and Simon Pegg - uniquely odd mixes. He's a self-described 'geek-boy' into Star Wars and sci-fi and comics and films - he claims to want to reclaim the word 'geek' for nerds everywhere. But when he shows up for the interview, he's a Hollywood-esque hour-and-a-half late, and in his baseball cap, baggy jeans and silver chain he looks like Tim, the slacker from Spaced, whom he calls his 'shadow self', but only after the stylists from Queer Eye for the Straight Guy have got their hands on him.

The lateness isn't his fault, it's Universal Pictures - he's running with the big boys now, and while Tim was an out-and-out loser, Pegg is almost absurdly successful. After Spaced, he co-wrote and starred in Shaun of the Dead with Edgar Wright, a zombie movie set in Crouch End. It was a low-budget first feature which, against all odds, went on to become a cult comic hit both here and in the States. Hot Fuzz is his and Wright's second cinematic effort together and it's hard to see it being anything but a massive hit, not least because Pegg now has one of the weirdest and most eclectic fan bases around.

There's the usual collection of obsessive-compulsives on the internet. But also: Quentin Tarantino, who championed Shaun of the Dead in the States ('If I'm in LA we'll have dinner or something'), David Schwimmer, who cast him as the lead in his directorial debut, ('Simon and I just naturally clicked, like salt and pepper') and Chris Martin, who's one of his best friends. He's even godfather to little Apple.

Did you have any idea when you started out that one day you'd be hanging out with Tarantino?

'None. It's all amazing. But luckily it happened quite gradually. The idea of doing some of the things that I've been lucky enough to do ... if I could have known that before, it would have been too much. I would probably have wet myself. And then cried.'

There's a lovely story which I assume is apocryphal about how, after Shaun of the Dead, an interviewer asked if he planned to carry on making films in Britain, to which he replied: 'Well, I'm not about to go and star in Mission: Impossible III.'

'I did say that!' he says. 'I really did. It was when we were doing press for Shaun and an interviewer asked if we were going to go Hollywood - as if you can't live here and still go and do films there - and I said, "Well, it's not like we're going to go away and do, I don't know, er, Mission: Impossible III." I pulled it off the top of my head. And six months later, I was like, "Hi Tom." What a hypocrite! It was fantastic, though. Really fantastic. JJ Abrams, who was the director, is a real film geek, like me, just a regular guy. And he saw Shaun of the Dead and liked it, and I got a call at the office one day and he said, "Oh hi, do you want to be in Mission: Impossible III?" And I was like, "Oh, OK then ..." It was my Jim'll Fix It moment.'

But then nobody could have predicted quite how popular Shaun of the Dead would be in the States. Robert Rodriguez, the director of From Dusk Till Dawn, led a standing ovation in Austin, Texas, and 'Tarantino did a private screening at his home - apparently he had pictures of us all up on the walls.' And he's quite earnestly humble when he talks about the amazingness of it all. But then he has that comedianly trait of being quite earnest about a lot of things. He wrote his dissertation on 'a Marxist overview of popular Seventies cinema and hegemonic discourses', and when I roll my eyes and say, 'Oh there's nothing like a bit of hegemony,' he tells me that 'an awareness of the postmodern condition is still the intellectual bedrock' of his comedic method.

I'd like to scoff but, hell, it gets results. And he and Wright are hoping that Hot Fuzz will do for cop films what Shaun of the Dead did for zombie films.

'We started thinking about the cop genre and the whole notion of investing the British police service with some sort of cool because it just seems that the British cops are up against it in some ways - they wear jumpers, they don't have guns.'

The plot is loosely what happens when an over-achieving Metropolitan police officer, Nicholas Angel, gets transferred to the sleepy town of Sandford and is paired with local boy Danny, who's played by Nick Frost - Pegg's best friend and his best man, as well as his co-star in both Spaced and Shaun of the Dead. When they met, Frost was a waiter and Pegg a stand-up. 'We met in Chiquito in Staples Corner and became buddies. I just thought he was the funniest person I knew. I worked in comedy and I didn't think those people were as funny as him, so when I came to write Spaced, I wrote a part for him.'

It's all a bit incestuous, the comedy scene. After studying film and theatre at Bristol, where he set up a comedy club with David Walliams, he became a stand-up comedian and met Jessica Stevenson while doing a sketch show for Meridian, and Edgar Wright while developing a project at Paramount. Since then he's worked with almost everyone. The cream of contemporary comedy is in Hot Fuzz - Martin Freeman, Stephen Merchant, Bill Bailey, Steve Coogan, Adam Buxton. As well as more Great British character actors than even Harry Potter can provide employment for: Billie Whitelaw, Jim Broadbent, Bill Nighy, Edward Woodward, Timothy Dalton, Paul Freeman, Kenneth Cranham.

'We had a rule early on. We said let's try and populate the film with British actors who have been in Hollywood films and who have played bad people in Hollywood films ... We wanted an ensemble of brilliant actors playing really small parts. So the fabric of the village is made up of this really impressive cast of people who you glimpse every so often. So there's Paul Freeman, Stuart Wilson and Kenneth Cranham, people I'd grown up seeing in films. Paul Freeman was in Raiders of the Lost Ark for God's sake! I mean that film was a huge influence in my life, and suddenly he's playing a vicar in my film.'

In some ways, it's not so suddenly. He has worked hard at it, and he takes it quite seriously - Jessica Stevenson is alleged to have made him burst into tears on more than one occasion when writing Spaced. And when I email my friend Kevin Cecil, who wrote a part for him in Black Books ('we wanted to see him play a baddie, and he did it brilliantly') to get some gossip, he tells me that he's uniformly popular with more or less everyone. More excitingly, though, he tells me: 'He used to share a double bed with Nick Frost. They are the real Morecambe and Wise.'

It's an apposite comparison. Pegg's comic hero is Eric Morecambe, but unlike him he usually plays the straight guy. 'Did you really share a double bed?' I ask him.

'Actually we shared a single bed for a while. I was staying around Nick's place on the floor and that was too uncomfortable, so we slept top-to-tail and that was too uncomfortable, so we ended up sleeping the same way. It was a very gradual process into being OK sleeping with a hairy man next to you. And I think that infuses a lot of our work too. I think it's very easy to reduce the relationship in the film to having some homoerotic subtext, which it kind of is because that really does exist in a lot of action movies, particularly Lethal Weapon. But a more intriguing relationship is the heterosexual male fighting his programming to be affectionate to another heterosexual male. And it's the relationship between Angel and Danny that is the real romance of the film.'

More than anything else though, there's a very British sensibility at its heart - the am-dram society, the floral arrangement competitions, the Village of the Year contest. His mum is in the film as one of the judges, and she is still a leading light of the am-dram scene in Gloucestershire.

'I grew up around a really passionate group of people who were doing theatre for nothing, doing it simply for the sake of doing it. And that's where I got my love of it from.'

His father 'lives for his music' - he's a jazz musician by night and a keyboard salesman by day - but he split from Pegg's mother when Simon was seven. He went to the local comprehensive, used to do a performance spot during morning register and, according to his old teacher, went through a rough time when his stepfather left home during his teenage years.

Not that he tells me this. He's visibly uncomfortable talking about his private life. He tells me his wife is called Maureen. 'I can tell you that because it's already out there, but apart from that it's not something I want to talk about.' I'd read that she works in PR, but he won't even confirm this, although the papers reported the starry turn-out at his wedding in Glasgow in 2005, including most of Travis and Coldplay, and David Walliams. While he happily admits that most of his work has an autobiographical element to it - Shaun of the Dead was set in Crouch End because that's where he lived, Tim from Spaced was obsessed with Star Wars because so was he - and he once told an interviewer that the stepfather in Shaun of the Dead was influenced by the slightly troubled relationship he'd had with his own stepfather, he denies this now too.

And then there's his celebrity pals. Tom Cruise is a 'great guy', as is David Schwimmer. But it's obvious that I'm not supposed to ask about cosy nights out round Chris'n'Gwyneth's. He concedes that he's been friends with Chris Martin since 'I met him at a gig around seven years ago', but then the shutters come down. 'He doesn't talk about his private life, so I'm not about to.'

'Oh come on,' I say. 'On the one hand, you're Mr Normal Bloke living in Crouch End, but on the other there you are mixing it up with the Hollywood A-listers. Isn't that a bit odd?'

'They're just normal people. They come in for a lot of stick. But it's all lies. It's all just bullshit. All this macrobiotic crap and yoga and you know.'

'So what? You're telling me that Gwyneth comes round for a nice juicy steak?'

'She loves a drumstick. She smokes 40 a day. And she can't get enough of McDonald's. Other people make stuff up so I might as well too.' And then he rants about what it's like being a celebrity in the age of Heat and the cameraphone: 'Like being in the Matrix: everyone's an agent'.

It's fair enough, of course. They are his friends. Although, whether he likes it or not, it sets him at one remove from us, the little people. That's success for you though, what happens when you cross Hollywood with the West Country, but I can't help feeling that we should cheer him on as one of our own.

A life in comedy

1970 Born in Gloucester.

1991 Graduates in Theatre, Film and Television from the University of Bristol.

1995 Gets screen break on ITV sketch show Six Pairs of Pants

1998 Stars in the absurdist sketch show Big Train with Mark Heap (Green Wing) and Julia Davis (Nighty Night)

1999 Plays lead in critically lambasted sitcom Hippies, written by the team behind Father Ted. Nominated for a British Comedy Award for his role in Spaced.

2001 Lands his first dramatic role in mini-series Band of Brothers, produced by Steven Spielberg and Tom Hanks. Guest stars in Chris Morris's Brass Eye paedophile special.

2004 Co-writes and stars in zombie comedy Shaun of the Dead

Kin of comedy

David Walliams

Studied Drama with Simon Pegg at Bristol University. In 1996 he co-wrote Asylum, a surreal sitcom starring Pegg, with director Edgar Wright (Shaun of the Dead). Had a cameo role in Spaced

Bill Bailey

In 1998, Bailey wrote and starred in Is it Bill Bailey?, a comedy series featuring Simon Pegg and directed by Wright. Bailey got his first sitcom role as Pegg's boss, Bilbo Bagshot, in Spaced

Ricky Gervais

Played a dodgy newspaper-advertising salesman in series two of Spaced. Gervais's co-star, Stephen Merchant, appears in Pegg's latest film Hot Fuzz.

Jessica Stevenson

Appeared with Pegg on short-lived show Six Pairs of Pants in 1996 and sitcom Asylum (1997). They then co-wrote and co-starred in two series of Spaced

Nick Frost

While a waiter, became Pegg's best friend. Pegg gave him a lead role in Spaced. He also stars in Shaun of the Dead and Hot Fuzz.

Win tickets

We have two pairs of tickets for a Hot Fuzz screening (introduced by the director) in London on 10 February and two pairs for a double bill of two films which inspired Simon Pegg (Bad Boys II and Point Break) on Friday 9 February at the Hot Fuzztival at the ICA (ica.org.uk). For a chance to win email review@observer.co.uk and put Hot Fuzz in the guidefield.

· Additional reporting by Tancred Newbury. Hot Fuzz opens on 16 February