Chris Hemsworth had to slim down for his new movie 'Rush'.

While the hunky 29-year-old actor packed on muscle to star in 'Thor' and as the god of Thunder in 'The Avengers' and the 'Thor' sequel, he was forced to drop weight to play Formula 1 racing star James Hunt in the upcoming film 'Rush'.

Chris told Esquire: "Thor is large. For that I had to add some muscle, which hasn't been all that hard so far. I like training just fine, thanks. But to play a Formula 1 driver, I had to drop quite a bit of that. You know, slim it down.

"First time I looked at a Formula 1 car in person, I just stared at the cockpit, figuring I'd never get in there. The drivers wear the whole car like a tight-fitting suit. So I just started training differently, shedding all that Thor. I've come to see size as just a kind of prop."

While Chris is a fan of racing, he admitted he prefers motorbikes to cars.

He explained: "I grew up in a culture of motorbike. So I like racing just fine. Quite a lot, actually. That was when I was a boy in Australia. And I never really made the jump to cars after that."