Jason Merritt/Getty

Chris Hemsworth is all muscle in Marvel's "Thor" and "Avengers" movies, in which he plays the titular hammer-wielding Asgardian, so it was with some trepidation that Ron Howard cast the Australian actor as lithe Formula One driver James Hunt in the high-octane drama "Rush."

Howard recalls, "Chris said, 'Thor can't even get in an F1 car -- but I will be able to.'"

Hemsworth made good on his promise, trimming 30 pounds from his beefy frame by switching from weightlifting to pure cardio.

"I was basically underfed and overtrained for a number of months, which led to a pretty moody existence," he tells Entertainment Weekly, joking that he "had more symptoms of a pregnant woman than [my wife]." His wife, Elsa Pataky, was expecting their daughter India Rose at the time.

"Rush" speeds into theaters September 27.

[via EW]

Chris Hemsworth Feels the 'Rush'

Rush Movie Poster
Based on 44 critics

In the mid-1970s, charismatic English playboy James Hunt (Chris Hemsworth) and Austrian perfectionist... Read More