Chris Hemsworth is trading in Thor's hammer for a Formula One race car in the upcoming drama "Rush," directed by Ron Howard. Based on a true story, the film follows the rivalry between drivers James Hunt (Hemsworth) and Niki Lauda (Daniel Bruhl) during the 1976 season.

While the risky sport required a certain amount of mettle from its entrants, Hemsworth insists Hunt was anything but a superhero. In fact, as movie-goers will see in the film, the driver suffered from such intense pre-race nerves, that he often vomited right before the starting flag.

"This guy had an incredible amount of cockiness and confidence, but there was a conflicted, anxiety-ridden kind of human there, and he was scared to death about racing because there was a 20 percent chance you'd die when you got on the track," Hemsworth explained. "Four or five of the guys would die in a year in the '70s and prior. So he lived with that — they all did — that looming threat. Some of the guys, Niki Lauda would study the fear and face it head on. James would distract himself from it. He'd drink and smoke and party to avoid the issue. Then he'd throw up before he raced."

Though Hemsworth confirmed that he isn't much of a "chucker" as he put it, he did admit to feeling a certain level of anxiety before auditions — or baring his bottom on screen, like he does in "Rush."

"It wasn't my idea. It was on the page," Hemsworth insisted, with a big grin. "It's an indication of who this guy was. He liked to get nude and sleep around. I was just playing the part, you know."

Co-star Olivia Wilde, who plays Hunt's supermodel wife Suzy Miller, confirmed that Hemworth wasn't coddled when it came to his nude scenes:

"With women taking off their clothes, everyone's polite. It's a closed set. Everyone's like, 'Are you okay?' When he did it was like, 'Chris, off!'"

And if you're holding out hope that his "Rush" experience might inspire Chris to expose even more, don't. He said of a potential full-frontal turn, "I had enough trouble and fear and anxiety getting the backside out let alone — no it won't be out there."

"Rush" opens in limited release Friday, going wide September 27.