LOS ANGELES (AP) -- He's about to introduce himself to the world as a cinematic superhero, but right now, Chris Hemsworth's biggest worry is a giant bowl of almonds.
Since taking on the title role in "Thor," the Australian actor has packed on more than 20 pounds of muscle to become the rippled Norse god of thunder — and the new body requires constant protein to maintain it.
"I needed to make an effort to get into the gym and force feed myself buckets of chicken and steak and vegetables and brown rice. It was rather sickening," says the affable actor, who looks like a young Brad Pitt with a sculpted physique that wows men and women alike. "But as far as jobs go, I don't want to complain. It's still one of the best."
Hemsworth had only a handful of American movie roles before landing that of the otherworldly Marvel superhero, which he introduces in "Thor" and will reprise next year in "The Avengers."
"Thor," which is directed by Kenneth Branagh and also stars Anthony Hopkins and Natalie Portman, opens Friday.
Hemsworth admits it was "sort of intimidating" to face his Oscar-winning costars, "but they couldn't have been more supportive."
"They all have the same sort of appreciation for the work and love for what they do," says the 27-year-old actor. "And there's no ego."
In casting the lead for "Thor," Branagh sought to discover "what was necessary: a real new movie star."
In fact, the film's producer, Kevin Feige, insisted that an exciting new Thor would be critical to the film's success, Branagh recalls.
"It's not something I ever mentioned to Chris Hemsworth," Branagh says, "but he was right."
The director wanted a fresh face, someone audiences could believe as a god, but with the acting chops of a veteran who could hold his own in scenes with Hopkins and Portman.
"He had all of that and he also had this kind of natural ease in front of the camera that was vital also," Branagh says of Hemsworth. "In repose, Thor must be a compelling story. And he is. And he's obviously a very handsome lad, and he worked like a Trojan to get that body. When he takes his shirt off, there's always an audible response."
(It's a safe bet that'll happen in a theater near you.)
Hemsworth says the muscles made him feel more like the character, but he's eager to shed the bulk. Still, it will be a while before he can: "The Avengers" starts shooting next week, in which the new Thor will join an ensemble cast that includes Robert Downey Jr. as Iron Man, Chris Evans as Captain America and Mark Ruffalo as the Incredible Hulk.
"It's a lot of superheroes," says Hemsworth. "It should be fun."
The middle sibling in a trio of acting brothers, Hemsworth and his younger brother (and former Miley Cyrus beau), Liam, both auditioned for the role of Thor. And though the brothers are competitive in sports — including their family favorite, surfing — they're a team when it comes to their Hollywood success.
"We're always supportive of each other, and if Chris gets a part over me, I'm as happy as him to get it as myself," says Liam, who is about to begin production on the much-anticipated big-screen adaptation of "The Hunger Games."
"A win for him is a win for me," echoes Hemsworth. "Having come all the way over here and it being a big risk, you need an ally."
The two rehearse together, share contacts and generally give each other professional pep talks.
"It's pretty incredible that my brother is a toy figurine now and there's posters of him everywhere," Liam says. "It's such a weird thing to think about... Most of what I've learned has come from him."
Both were inspired by their eldest brother, Luke, who became a TV star in Australia after high school and still works there today.
With "Thor" and "The Avengers," Hemsworth is hoping to parlay the family's biggest acting credit to date into a varied career that includes comedy and drama, big-budget pictures and independent films. He hopes to follow a path like that of Leonardo DiCaprio, Sean Penn or Russell Crowe.
"The options those people have is appealing," Hemsworth says, acknowledging that his casting in "Thor" has already resulted in new opportunities: "You spend so long standing in line hoping to be picked, so it's certainly been a good feeling."
But he's quick to clarify that it's not like Steven Spielberg is banging on his door.
"That's the dream," he says. "It's something that you want to aspire to. But I don't want to get ahead of myself. The film hasn't even come out yet."