The Oscar-winning actress and singer admits she was initially terrified of playing a heroin addict in her new movie The Inevitable Defeat Of Mister And Pete because she has never had a drink or experimented with drugs.
The 31-year-old star told Manhattan magazine: "It terrified me to play that part because I had no reference point. I'm 31 and I've never, ever, ever had a drink or done a drug in my entire life. I stick with Diet Coke and Crystal Light and water."
The Dreamgirls star was also nervous about taking on the lead role in her other new movie Winnie Mandela and admits it took a toll on her.
She said: "It was intimidating to play Winnie after seeing how much she means to the people there. To some she's an angel and to some she's Satan, but either way, woo!
"The strength that woman possesses is amazing. We put so much into the story, and it took a lot out of us."
Despite returning to the big screen, Jennifer is excited for fans to hear her upcoming new album, which will be released next year.
She said: "This record is not about me playing a part or me as a spokesperson. What we're doing feels so right that I never want to go home. My sister and my manager will be sleeping on the couch while we work until 4 or 5am."
- BANG! Showbiz