Sean Penn's latest film Into the Wild is attracting serious Oscar buzz for its depiction of a real-life adventurer who met a sorry end in the Alaskan wilderness. Star Emile Hirsch talks about the sacrifices he made to play the part.
In the flesh, American actor Emile Hirsch looks a picture of fresh-faced, clean-cut health and vitality.
Not so long ago, though, he was an emaciated shadow of his current self, having shed 41lb (18.5 kg) to play a young man dying of starvation.
That was just one of the ordeals the 22-year-old endured to play Christopher McCandless in Sean Penn's drama Into the Wild.
A college graduate who turned his back on a promising future, McCandless spent two years on the road before ending up completely alone in the Alaskan wilderness.
"Chris was a guy who felt cut off from the raw throb of his own existence," the actor says.
"He felt he'd been a rat in the rat race for too long.
"So he abandoned his family, gave all his money to charity and set off on a two-year journey across the country."
"He came from a wealthy family and he just gave everything up," Hirsch continues.
"His goal was to have this Alaskan odyssey - to survive alone with almost no supplies for as long as he could."
That expedition came to a tragic end in 1992 when his body was discovered by hikers in the abandoned bus that had been his makeshift home.
His story inspired a bestselling book by US writer Jon Krakauer - a book that Penn, with the blessing of the McCandless family, has now adapted.
"You pay a high price sometimes for wisdom and self-knowledge," says Hirsch. "But Chris was a good person who felt this is what he had to do.
"Who am I to say he should have done this or should have done that? I didn't walk in his shoes."
Hirsch may not have experienced everything his character did, but he certainly suffered his fair share of hardship under Penn's direction.
From kayaking through rapids and climbing steep, snow-covered hills to sharing the screen with a (trained) grizzly bear, the actor found himself pushed to the limits of his endurance.
"There's a scene where I float naked down an ice river that was very cold," he recalls with a shiver.
"I was very skinny at the time, so it was a huge shock to my body. Afterwards I had the first stages of hypothermia."
But Hirsch feels it was worth it all to work with Penn, an actor and film-maker he regards as a personal hero.
"I grew up being a huge fan of Sean's, so the chance to be around someone like that and be guided as an actor was a life-changing experience," he says.
The awards season has yet to begin in earnest, but Into the Wild is already emerging as one of this year's leading contenders.
Hirsch, though, says he has given little thought to his prospects of basking in Oscar glory.
"Of course it's exciting to have people talk about it like that. That's a huge honour right there," he says.
"But it's for other people to decide. You kind of have to look forward and just do your own thing."
Right now that means Speed Racer, an action adventure about a futuristic race car driver that will reach cinemas in summer 2008.
"The films I want to make are the films I would want to watch," says the actor. "That's the only way I know I'm being true to myself and committed to what I'm doing."
Into the Wild is out in the UK on Friday.