Just how “method” is Ryan Gosling? The 27-year-old actor and Oscar-nominated star of Half Nelson and The Notebook pushed actorly intensity to the limits for his new movie, Lars and the Real Girl, in which he plays a sweetly inhibited office worker who falls for a silicon sex doll. It's a performance balanced precipitously between comedy and tragedy and, to make it credible, the method supremo piled on an extra 20lb (9kg), lived in his character's garage and... “That's just bullshit man!” interrupts Gosling, scoffing broadly in the Toronto hotel bar where he is finishing a heavy day of movie promotion. “I'm not a f***ing method actor. When I was shooting Lars, nobody would talk to me for the first two weeks! I finally found out that the word on set was that I was a hardcore method actor. People said ‘You gotta call him Lars and you can't look him in the eye.' I was, like, ‘This is such bullshit!'”

Gosling's face is an amiable grimace of self-deprecation, buttressed by self-confidence. He is aware, you suspect, that he is consistently described by Hollywood insiders and awards juries as the brightest actor of his generation - the new Ed Norton/Paul Newman/James Dean. “Acting's just a job for me, and it's certainly not art,” he adds, with the casual disdain of a Brando or an Olivier. He admits, nonetheless, that Lars and the Real Girl required more actorly craft than most, just to pull it back from the salacious, the creepy or the plain absurd.

“I saw it as a Ken Loach-type movie about a guy who met a girl, fell in love and found out that they had similar hopes and dreams,” he says. The film, from an Oscar-nominated script by the Six Feet Under writer-producer Nancy Oliver, and co-starring Emily Mortimer and Paul Schneider, examines the effect of Lars's eerie infatuation on his local community. Here, as he drifts around town with his sex doll, now called Bianca, fully clothed and in a wheelchair, it becomes clear that he is delusional but that his love for Bianca is utterly innocent. “I never really thought of Bianca as a doll,” he says. “It was always a very real love story to me, and that's the way I played it.”

It's all a long way from the squeaky clean Canadian pre-teen that he once was, busting some moves as a boy-band moppet opposite Justin Timberlake and Britney Spears on the Disney Channel's Mickey Mouse Club. There's some great footage on YouTube, I tell him, of his 12-year-old self dressed in a grey silk pyjama suit and beating his chest with a stiffened hand, which is boy-band semaphore for “Ya know ah love ya, girl.”

“Yeah, man, there's some great stuff there,” he giggles, cringing. “You can't hide any more. The days of selling some kind of image are over.”

But even Gosling's clean-cut TV adolescence was something of a feint. The son of divorced Mormon parents from Cornwall, Ontario, Gosling saw TV work as a way to escape the two things that he hated most - school and, well, childhood. “I hated being a kid,” he says, stony-faced for the first time. “I didn't like being told what to do, and no one ever asked me my opinion.”

Gradually he built up a screen career. His role as Danny Balint, the conflicted Jewish neo-Nazi protagonist of The Believer, changed everything. “I couldn't have been more wrong for that part,” he says. “I was 19, non-Jewish, and from Canada, playing a 26-year-old Jew from Queens. But I ended up operating on instincts I didn't even know I had.”

The Believer, disturbing and award-winning, and driven by a toweringly physical performance from Gosling, transformed the young tyro, now living in LA, into the hottest prospect in town in others ways, too. His subsequent Murder by Numbers co-star Sandra Bullock, for instance, elided a 17-year age gap to date the actor in 2002, while his fiery onscreen relationship with Rachel McAdams, his The Notebook co-star, became a three-year romance that ended recently in turbulent style when, he claims, “We both went down swinging and we called it a draw.”

It was also on The Notebook that Gosling's reputation as a method-acting madman was fully established. Here, while preparing to play a lovestruck carpenter, he became a fulltime woodworker's apprentice. For his follow-up role, playing a crackaddicted teacher in Half Nelson, he would shadow an inner-city teacher for weeks. And still, there are the denials. “Just because I made furniture for The Notebook, everyone thinks I'm method!?” he says, exasperated. “But that stuff doesn't matter, and nobody can tell anyway.” He shrugs, shakes his head and adds, crucially: “You do that stuff for you, because it makes you feel like you're doing something to justify the stupid amount of money they're paying you to do this thing that's pretty easy.”

This is not arrogance, this is simply Gosling in full flow. This is an actor, unlike most Hollywood actors, who feels that he has nothing to lose. He was recently bounced from Peter Jackson's highly anticipated Lovely Bones adaptation. The producers said that it was about creative differences, Gosling says that it was about his character's age, but secretly you hope that it was his devil-may-care recalcitrance that rattled the studio mindset. Similarly, his next big project, after a thriller with Kirsten Dunst and a romantic drama with Michelle Williams, is a self-financed movie about the child soldiers in the Lord's Resistance Army of Uganda. “We almost have all the money,” he says. “I'm pretty confident that we're going to do it this year.”

In the meantime, don't expect to spot him gadding about in Hollywood hotspots. Instead, the less salubrious downtown LA is Gosling's home turf, complete with wandering junkies and poverty. No, really. “I want a sense of community, and downtown is the only place you can get it in Hollywood,” he explains. “It's full of crack-heads, but at least they will talk to you. And there is one store where I help out - I man the cash, and make sandwiches for people.” He smiles, and adds: “It's not about me. It's simply part of life.” He says this with the confidence of someone who knows which part of life, exactly, is real.

Lars and the Real Girl is on selected release from Friday

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