The stunning 29-year-old actress has several sex scenes and a revealing shower sequence in the film, about an assassin who is set up by his employers and sets out to seek his revenge.
Jessica, a mother-of-one, told one of the directors Robert Rodriguez, that she "wasn't comfortable" with stripping off, and so the underwear she wore while shooting was digitally removed afterwards.
"But I've never been very comfortable with that stuff. I get freaked out and nervous, I guess, so I told Robert, 'This is an awesome movie and I'd love to be a part of it but I don't feel comfortable doing that', and he was like, 'Oh, we'll rewrite it and we'll do what you are comfortable with'," she told British newspaper The Independent.
Jessica - who is married to Cash Warren - revealed that once her two-year-old daughter Honor is in bed she throws parties at home and lets loose with her friends.
"I think I'm actually a little more wild and free since I've had her because, once she's in bed, all my mom friends, we get together and have dance parties at the house," she confessed. "It sounds really dorky but it's true. It's certainly something I wouldn't have done before."
