It seems a bit rude to kick things off like this but Mackenzie Crook has made a career out of being a bit, well, funny-looking. Whether it's boggle-eyed Gareth in The Office, his greyish pallor offset with bowl cut and oversized Next suit, or gormless Ragetti, the lank-haired runt of a swashbuckler whose "wooden eye" pops out at the most inopportune moments in Pirates of the Caribbean, directors have emphasised the 38-year-old actor's ability to look very odd indeed. He's resigned himself, he says, to the fact that he's rarely given a flattering make-over. He even got married sporting Gareth's pudding bowl because he was mid filming. "I tried to disguise it with 'product'", he says wearily. "But it was definitely there." His wife-to-be must have been thrilled? "There was nothing she could do – and she was over the moon to be marrying me, I'm sure."
Today, though, off-duty and dressed in a baggy Nirvana T-shirt and thick-soled Doc Martens, with chunky silver jewellery and a trucker cap pulled low over his eyes, Crook looks a little hippyish, definitely quite skinny but on the whole, really quite disappointingly normal. So it must be irritating when people tell him, as they do, that he ought to audition to be the new face of Mr Muscle, say, or that he looks like tubercular medieval monk or a junkie, or a crow-pecked scarecrow, or, indeed, when he gets asked for ID when he tries to buy cigarettes. "It used to wind me up a bit. I've totally got used to it now. I know I'm thin and everything but people project a pallid look on to me that I don't necessarily think I have. I would come back from months filming Pirates in the Bahamas with a tropical tan and they would still see me as a pale and unhealthy-looking. I couldn't do anything to make myself look any better in their eyes. I was just weird Mackenzie Crook." At school, he was always known as the small kid or, once a dose of growth hormones had taken effect, the skinny one. "But nobody ever called me the 'weird, sunken-eyed cadaver' or whatever they describe me as these days. But you know, I've got a lot of jobs because of the way I look. That's fine by me."
Perhaps because of his distinctive looks, people seem to find it particularly difficult to separate Crook from his most memorable creation. Men are forever hanging out of vans and pubs and yelling "Gareth!" at him as he scuttles along the street. Some days it's great. Other days, he says, it can be a "pain in the arse". "I seem to get it more than a lot of other people who are more famous than me", he says. "When I was working with Christian Slater on One Flew Over the Cuckoo's Nest, I'd walk down the street with him and I'd notice people spotting him and whispering to each other. Then they'd spot me and shout 'Aaaaahhhhhh! There's that bloke! Gareth!' So they'd whisper in awe about Christian but they'd point me out to everyone and laugh in my face." He's not much troubled by the paparazzi, though. When a couple of photographers turned up outside his house last year, he was so surprised, he rang up his agent. "I said, 'am I in the news?' I wasn't."
In person, he is quiet, shy (painfully so, at first), earnest and just nicely nerdy. He is also full of surprising, mumbled anecdotes, once you look beyond Gareth and rummage about a bit. Did you know, for example, that he lives in Peter Sellers' old house in Muswell Hill in north London? Michael Sellers told him that he remembered his father turning the kitchen into a dark room which annoyed his mother no end as she tried to wash up in a sink full of chemicals. "There's also a beech tree at the bottom of the garden which Peter Sellers planted which is now huge", says Crook. "I do love it."
Or what about the fact that he has four tattoos? His children's names, a turtle and, bit of a shock, this one, a vast, lurid Pirates of the Caribbean skull and crossbones which takes up the whole of his left upper arm. "I'm not out to cover myself", he says shyly, rolling his sleeve back down. "But I like it as an art form." And then there's the story about when he first had a bit of Hollywood money to burn three years ago and thought of buying the Ferrari Testarossa he'd dreamed of as a child. But then, "I suddenly realised I can't justify that. I can't claim to be an environmentalist and then buy a sports car. So I decided to buy the opposite."
The "opposite" was eight acres of protected woodland in the Kent countryside. Crook has always loved the natural world and still has vague dreams of becoming a farmer. Growing up in a village outside Dartford, he would go on bike rides with his father and sisters down the country lanes, learning the names of flowers and picking fruit to make wine. Summer holidays were spent running wild on his aunt's farm in Zimbabwe. He hopes the wood will fire the same enthusiasm in his children, Jude, seven, and Scout, two. Gareth, without doubt, would have bought the Ferrari.
Fittingly, Crook is currently back on stage in Jerusalem, Jez Butterworth's magnificent paean to England's rapidly disappearing green and pleasant land, which arrives in the West End from the Royal Court garlanded with awards. "The setting is quite similar to where I grew up", he says. "I've got this fondness for it now, in hindsight, but at the time, I didn't much like the small-mindedness of it. I wanted to get away." Crook plays Ginger, sidekick to Mark Rylance's local legend Johnny Byron, a drug-guzzling daredevil who lives and raves in a caravan in the woods. The two stars asked if they could share a dressing room at the Apollo, as they had done at the smaller Royal Court. "We run the lines between us, have a glass of port..."
Crook loves the theatre. He's appeared in just three plays, all of which have been smash-hits. His debut was playing stammering Billy Bibbit in One Flew Over the Cuckoo's Nest which transferred from the Edinburgh Fringe to the West End in 2004. Then in 2007, Ian Rickson (who also directs Jerusalem) cast him as Konstantin in The Seagull, opposite Kristin Scott Thomas and Carey Mulligan. Critics praised, perhaps with a hint of surprise, Crook's "touchingly truthful" and "shimmering" performance. "I wasn't convinced I could do it. It wasn't the sort of part that I'd ever been asked to play before", he says. "It was very exciting to be offered something with a bit more depth. There was a real danger of me just being the comedy weaselly bloke in every script. I really had the most profound time doing The Seagull. I've never been so artistically fulfilled." The production transferred to Broadway, where Hillary Clinton, Robert De Niro and Al Pacino came to see it. "The class of celebrities", he sniggers, with a hint of Gareth "... is just different on Broadway. More exotic."
Crook didn't go to drama school. He trained the hard way, over 10 back-breaking years on the comedy circuit. At school, he was "witty enough", drawing caricatures of his teachers in his exercise books to amuse his friends. There was no drama department at his all-boys grammar, so he joined a local youth theatre. Having "completely lost interest" after his GCSEs, he failed his A-levels, made a "really half-hearted" attempt to get into art school and wound up working in Pizza Hut and as a hospital orderly.
In his early twenties, he escaped to London where he tried out comedy with two characters – Charlie Cheese, "the world's worst light entertainer", and Mr Bagshawe, the geography teacher from hell. "I cleverly came up with characters that it didn't matter if they were heckled", he says. "I wouldn't want to try stuff as myself." He took four shows up to Edinburgh where he was spotted by Bob Mortimer who put in a good word which in turn led to The 11 O'Clock Show. Suddenly he was on television three times a week with Sacha Baron Cohen, Ricky Gervais and Iain Lee (with whom he shared a flat). "We felt like rock stars. It was a really exciting time." His parents, though, were worried about him, haring about from gig to gig, getting changed in pub toilets. Did they ever think he'd make it? "No. I don't think so, to be honest."
Then came The Office. "I knew as soon as I read the pilot script before my audition that this was the one I had to get", says Crook. The rest is Bafta- and Golden Globe-decorated history. He'd work with Gervais and Stephen Merchant, "generous, funny blokes", again in a heartbeat. "I would do anything that they wrote – if they came to me with a script. If it wasn't Ricky and Stephen writing it, I'd have to look very carefully. Any sitcom that I did would be compared to The Office."
In the immediate aftermath, Crook turned down endless Gareth-esque parts, though not, unfortunately, a couple of lame British comedies, Sex Lives of the Potato Men (voted worst film of 2004) and Three and Out. "I've tried to remain true to myself and do things that I find interesting or challenging. But it's easier said than done sometimes. I spent a lot of years not making much money at all and to turn down any job is really difficult at first", he sighs. "Though I was probably a bit disappointed by the way Sex Lives came out – it's not my favourite – a lot of people, especially cab drivers, love it." Does he take criticism badly? "It is difficult when people have been so nice about other work and you think, 'oh no, what have I done? I've failed them'. But you soon get over it. I've learned to check things, be a bit more thorough."
He's had far more luck in Hollywood. A bit part in the J M Barrie biopic Finding Neverland saw him working with Johnny Depp, who pushed Crook for Pirates. He's now filmed three of the movies but is not signed up for the fourth. "Noooo", he whistles through his teeth. "They haven't asked me. But actually I don't mind that at all. I'm a fan of the first one especially and I think the trilogy we've made is great. I'd almost like them to leave it there." Quit while you're ahead, Office-style? "I'm a big fan of that. If people want more, then, sure, give them more if you can keep the standard. Quite possibly they do and quite possibly they can, so that's great. But my pirating days are over."
He enjoyed the blockbuster experience (and has the tattoo to prove it) but was badly homesick for his young family. His wife Lindsay brought Jude to visit him on set. "My son's got the biggest carbon footprint of any child. He's not into pirates particularly, though. He prefers Doctor Who", says Crook. "It wasn't the Caribbean holiday that everyone imagines. There were times when it was quite tough. There's a reason why holidays are two weeks long: when you're in the Bahamas in a resort for months on end, you start going crazy, become an alcoholic... I went fishing a bit. But after a while this depression would start creeping in. You're in this tropical paradise but you can't be bothered to go out and do anything at all."
His latest brush with Hollywood has been filming Steven Spielberg's Tintin with Daniel Craig in LA, leaping about wearing pyjamas covered in dots for the motion-capture movie. But, really, he'd be just as happy leaping about in the woods with his kids. "I've had the time of my life so far – I love it. It's the best job in the world", he agrees. "But if it all dried up tomorrow it wouldn't bother me particularly. I'd find something else to do."
'Jerusalem' is at the Apollo Theatre, London W1, to 24 April (0844 412 4658)