The 30-year-old, who is engaged to singer-actor Justin Timberlake, plays resistance fighter Melina in the remake of the hit film, which sees her battle with Kate Beckinsale, reported Contactmusic.
"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," Biel said.
The actress, who has featured in successful films like "The Illusionist" and "The A-Team", said that she has to work hard to look good in her films but gets bored of dieting.
"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," she added.