Lonely Hartnett

Partly, Josh was angling to be thrown out anyway; he'd been spotted performing and invited to Hollywood to audition for Terrence Malick's The Thin Red Line. 'So I went home for Christmas, went to LA in January and was there for two weeks before I landed a job.' It wasn't the role in the Malick film, unfortunately, but in the American version of Cracker. Josh swallowed his disappointment and launched himself into his career.

He recently discovered that, in fact, he did get the The Thin Red Line role as well. 'I met the casting director who said to me, "We were curious about why you took the TV show instead,'' he says. 'I said, "You mean I got the part? Nobody ever told me!" Terrence Malick is a genius. I'd have loved to work for him. But there was more money in TV.' So his agents had deliberately not told him of the film role. 'That's Hollywood. It's horrible, right?' To add insult to injury, Cracker was cancelled after nine months, while The Thin Red Linewas nominated for seven Oscars.

It was the first in what Josh regards as a series of betrayals by Hollywood. The next came immediately afterwards, when he was scooped up by the Weinstein brothers who founded Miramax. They insisted he took a role in Halloween H20: Twenty Years Later as Jamie Lee Curtis's son before they would cast him in The Faculty (frankly, an equally silly-sounding film about alien teachers).

Even so, after his role in Sofia Coppola's The Virgin Suicides, Josh was beginning to get a good reputation as a young talent to watch. That was before Pearl Harbour, which came out just as he wrapped on Ridley Scott's Black Hawk Down.

'Up to that point, I'd done eight little films and the critics liked me,' he says. But Pearl Harbour was over-hyped and under-scripted. 'And nobody likes being told what to think. So the critics went, "Why are we supposed to think he's a movie star; we'll just hate him forever then.''' He laughs ruefully, but his acting skills are not developed sufficiently for him to conceal the real rancour that remains. Josh refuses to admit regrets: 'There's no point. I can't go back and change it. Who knows what might have happened if I hadn't done it? I could have been a critical darling, but felt lost anyway.'

It was the failure of Pearl Harbour (a flop so expensive it led the chairman of Walt Disney to fall on his sword) that sent Josh scurrying home to Saint Paul to be reunited with his family. 'I went through an extreme loner phase from when I was 17 to about 21,' he says. 'I lost contact with my brothers and sister. I didn't have much to do with anyone.' (Now, in an effort to make up for that lost time, he's employing his sister Jess, a shy, dark girl with a smidgen of his glamour, as an assistant.) But where most actors might have hidden away for a couple of months, licking their wounds, before re-emerging into the spotlight, Josh spent two years valiantly pretending that his foray into Hollywood hadn't happened.

He got back together with his high-school sweetheart, Ellen Fenster, and they set up home together. Josh occupied himself working for local charities. 'For sure, at that time I had no interest in coming back,' he says. 'It was an odd time. My only connection with the industry was writing a script with my best friend.' Did he get bored, I wonder? 'Pretty much,' he admits. 'And then Black Hawk Down comes out, there's media attention, and nine months into my self-imposed exile, I get asked to come and present the Oscars. And it's the Oscars, it's kind of fun. So I went with my girlfriend and we had a weird little time.' He sighs. 'Hollywood, it's like the Mob, it just keeps pulling you back in.'

He did his best to resist, refusing the superhero roles that were offered to him - 'the characters weren't what I wanted to play' - but eventually, one studio made him an offer he couldn't refuse: costarring, with Harrison Ford, the screen hero of his youth in Hollywood Homicide. Even so, Josh's first foray back into films wasn't happy. 'It was a tough shoot for me because I was only half there,' he says. 'I was staying in a hotel in LA, my girlfriend [Ellen] was with me, but we weren't really going out and it felt uncomfortable.' On set, he was overshadowed by Harrison Ford. 'I had input before he was cast, but then the power started to shift. Harrison was working with the producers and directors, and I was like the kid who had to be shooed away. Harrison's a tough guy. He wasn't all warm and fuzzy on set, that's for sure.' And that might have been that, the end of Hollywood dreams, if he had not met the director Paul McGuigan, with whom he felt an immediate connection. They went off together to Montreal to make Wicker Park, a remake of the French film L'Appartement, which he says was 'strangled by the studio'. Two years later, they collaborated on the more successful Lucky Number Slevin, by which time he'd notched up creditable performances as a hitman in Sin City, as a morally corrupt cop in The Black Dahlia and as a man with Asperger's syndrome in Mozart and the Whale.

Next up is I Come with the Rain, a dark film by the Vietnamese director Anh Hung Tran, in which Josh plays a private eye who goes to Hong Kong to find the son of a Chinese billionaire but ends up losing his mind.

Strangely, it seems to have been yet another failure that has made Josh come to terms with his success. This year, he produced and starred in August, about a dot-com company struggling to survive. Once again, the moneymen scuppered his plans, payinglip-service to the contract by showing the film at one New York cinema, then sending it to DVD.

Rather than rage against his own powerlessness, Josh has decided to change things by becoming more of a player. His first move has been to agree to star in an Armani fragrance ad for Diamonds for Men. It's the sort of thing that would have had the old Josh running a mile - the camera lingers lovingly on his naked torso, he's clawed by beautiful and lust-maddened women, but these days, he's taking the long view.

'Oddly enough, it really helps me make independent films,' he says earnestly. 'There's been a major shift in Hollywood actors doing press-related advertising. These days nothing says movie star more than doing a perfume ad - I'm not kidding you. So instead of going off and doing movies I don't believe in, I've done this.' So he feels good about his motivation and integrity, and the rest of us can see him with his shirt off. That's what I call a result all round.

Rain Man is on at the Apollo Theatre until 20 December