The actress, who is engaged to Justin Timberlake, said that she didn't find the action scenes in the remake of hit film Total Recall scary because she has never been particularly girly.
Biel plays fighter Melina in the new movie, which sees her battling it out with Kate Beckinsale in the physical scenes.
On whether she has a reputation for being tough, she said: "Maybe not tough, but perhaps tomboy.
"I've always been that kind of person - constantly playing sports and never really into make-up or fashion, until about five years ago."
The A Team star admitted that she has to work hard to look good in films but that she finds dieting a bore.
She said: "There are some days when I feel like I can't eat another chicken breast and if I see another piece of broccoli, I swear to God...
"I know I feel better when I see myself on screen and I've been really dedicated, even though it was a pain in the ass. It's there forever and you get one chance."