Chris Hemsworth over eager with Thor workouts

Chris Hemsworth had to have his 'Thor' costume altered because he'd bulked up too much.

The actor takes on the role of the action hero in the big-screen adaptation of the iconic Marvel comic book but admits he went a bit too far with his weight gain.

He said: "I got the part and immediately started looking at the comic books, and the guy is 500 pounds or something and looks like Schwarzenegger. And I thought, 'OK, I'm not gonna get to that.' But I have to get bigger.

"The filmmakers kept saying 'Yeah, get as big as you can, as big as you can.' And then I came back right before Christmas, just before we started the movie, and had a final sort of camera test and put the costume on and within a couple of minutes, my hands started going numb," he recalled. "And everyone was like, 'Yeah, that's not cool.' And I started getting pins and needles and you'd touch the skin and the blood wouldn't return to that area so quick. And I thought, 'OK, it doesn't fit.' "

The costume had to be changed and director Kenneth Branagh told him to "pull back" on his intense workouts and now Chris is looking forward to the highly-anticipated film being released in May.

He told the Los Angeles Times: "It's the normal sort of anxiety that you want it to succeed and do well."