Josh Harnett: 'I'm not so hot on the hottie tag'

By this time next week the critics will have seen, and delivered their verdicts on, Josh Hartnett's West End debut in Rain Man. Not that the 30-year old movie star is too bothered. "The critics always give me a hard time so what do I care?" he says. "In the West End at least there are more critics so there's more chance at a fair trial. There's only one critic that really matters on Broadway and if they don't like you, you're screwed. The chances of The New York Times shining to a Hollywood actor coming in for his first play are slim. I would be hanging myself in New York."

That said, it's not exactly been a smooth ride for Hartnett since he arrived in London a little over a month ago. The production has been dogged by rumours of discord, with a last-minute change of director (Terry Johnson replaced David Grindley) putting opening night back by a whopping 10 days.

And then there's Hartnett's run-in with the British tabloids: he's suing The Daily Mirror for a story, which, playing on his links to some of the world's most beautiful women including Scarlett Johansson and Rihanna, alleged that he had a "sexual dalliance" in the library of the Soho Hotel. "I'm not going to say that I'm a saint, that I've never done anything wrong in my life, but if you're going to find something out about me personally, at least find something that's remotely true", he grumbles.

He's finding it hard to enjoy London thanks to a permanent tail of photographers. Though he's dressed down today in a black long-sleeved T-shirt, grey hoodie and tortoiseshell Ray-Ban wayfarers, there is something unmistakeably Hollywood about Hartnett. As he tucks his 1.9m (6ft 3in) frame behind the tiny table in a chi-chi café on Marylebone High Street, two girls sidle past crab-like, unable to tear their eyes away from him while the waitress lingers just a little too long as she delivers his latte.

He still managed to make an unannounced cameo in a midnight performance of Hamlet at Shakespeare's Globe last weekend with the super-cool company The Factory, who stage their pop-up plays all over London. "It was a goof", he breaks into his first smile. "They ripped out a page of the book and said 'here you're going to do this'. It looks like more fun to be a part of than anything you can imagine on stage."

Back in his day job, Hartnett plays Tom Cruise's part, Charlie Babbitt, in the new stage version of the Eighties film while Adam Godley plays his autistic brother, which was an Oscar-winning turn for Dustin Hoffman.

"I didn't take on the role that would showcase me in the best light," he says. "Nobody's gonna come out of the play and say, 'wow, a tour de force performance by Hartnett'. It's geared towards the Rain Man but the more interesting character in my mind is Charlie because it's the harder sell."

This is Hartnett's first stage outing for 12 years, since he performed The Threepenny Opera at drama school. "But I've never been the star of a play in front of an audience this big. I got lucky when I was really young – I worked my ass off to get there but nobody really saw that. I've been considered just a kid who was handed this career."

Hartnett grew up in Minnesota. His father played guitar with Al Green and his siblings, Joe, Jessica and Jake, all have musical careers. On leaving Catholic school ("I did my Bible learning but I made the decision not to be religious aged 12."), he entered the theatre programme at the State University of New York. Legend has it that he was plucked from there for stardom. In fact, he was "kicked out" after six months. "I knew I had options and I pushed my luck."

With an audition for The Thin Red Line under his belt (he didn't get it), he wrote to the dean of the programme telling him that constant evaluations were strangling the students' creativity. The dean, he says, responded by asking him to leave. Once in Los Angeles, he did 14 auditions and in two weeks had landed two parts, the first in the US version of Cracker. Then he was cast in The Virgin Suicides and The Faculty. His cool, critically-acclaimed turns led to the blockbusting parts in the million-dollar flop Pearl Harbour and Black Hawk Down. "Up until that point, I had the critics on my side. They were really digging what I was doing. Then Pearl Harbour was the mega-publicity event that it was – and nobody likes to be told what to like. I had people who wanted to tear me down after that. It all happened really quickly; I was 21 years old."

So he did the unthinkable. "I quit. Why would I expose myself to that? Everybody screwed me when I wouldn't even be out of college in my real life." He escaped home for nearly two years, wrote a movie with his best friend (Wish You Were Here, which Dreamworks bought but never made), painted and turned down every part he was offered, including a trio of superheroes – Superman, Batman and Spiderman. "I had to change agents after that".

Wasn't he a tad tempted by Superman? "Are you kidding? No. A role like that can define you and it's not a very flattering definition. It doesn't make people think 'wow what an artist'. You have that 'S' imprinted on your chest for the rest of your career." Were his two highest profile films an anomaly then? "Totally".

The chance to star opposite Harrison Ford in Hollywood Homicide broke his hermit-like resolve but his choices since have been resolutely lo-fi and indie. "There hasn't been anything that I've gone into thinking, 'this is going to be crap, I'm just doing it to help my career'. Not one thing. So I can sleep well."

He has been unveiled though as the chiselled face of an Armani aftershave in billboards which feature him being pawed by women as flashbulbs go off. "That was strange", he admits but says the high profile it gave him has allowed him to green-light various independent projects, including the upcoming August, about a dotcom millionaire and I Come with the Rain, with the French-Vietnamese director Anh Hung Tran. Hartnett turned 30 this year and stopped smoking to mark the occasion. "It was terrifying before [the birthday] happened. I remember feeling old when I was 22. But now I'm the same age as my dad was when he had me, I'm old enough to be a father." So he's ready to settle down? "I don't think I can right now, there's a lot of things I want to do."

At home in New York he avoids the limelight by hanging out with musician and artist friends and concedes to one set of famous pals, Kings of Leon – "they were supposed to come to my play last night, then didn't show – bastards". He's "more of a music fan than a movie fan" and listens to Wolf Parade and Bon Iver, music that reminds him of childhood summers at his family's log cabin in Wisconsin. And he reads constantly, fishing excitedly in a manky plastic bag for the books he bought at the Oxfam shop on the way to our interview: The Sheltering Sky, The Fountainhead and a little-known Gabriel Garcia Marquez ("one of my favourites"). He lays them on the table, obligingly turning the spines towards me so I can copy down the titles.

In this one endearing move you sense Hartnett's overwhelming desire to be taken seriously. And there's no reason why he shouldn't be, having made braver and more interesting artistic decisions than most. But, unfortunately for him, it seems it's going to take more than a few indie films and a stint on stage for him to shake off the Hollywood hottie tag. As he lopes out of the café, he leaves a gaggle of star-struck waitresses in his wake. "Was it him? The one from Pearl Harbour?", they twitter in the doorway. "Yes it was, and he's in that Armani advert."

'Rain Man', to 20 December, Apollo Theatre, London (0870 040 0046)