The `A-Team` actress - who is engaged to Justin Timberlake - thinks she needs to rid herself of her good girl image and believes it is time to be "very bad".
She said: "I think I need to destroy my reputation. This whole, `I`m outdoorsy, I`m really healthy` - it-s too squeaky clean. That`s going to be my new thing, go dark and unhealthy. It`s time to be very, very bad."
The 30-year-old beauty admits she was not always so girly and used to make her Barbies have "sex" with each other and once cut their heads off to make Christmas lights.
She told W Magazine: "It was always, `Let`s play sex with Barbies!` My Barbies were usually naked.
"Once, I took their heads off, cut their hair, drew on their short, spiky hair with some markers, then stuck the heads on Christmas lights. Every year, we`d string our tree with those Barbie heads. It looked demonic. My parents were so cool-they saw it as a form of self-expression.
"I never identified with girls. Girls were nervous about going into caves. They were scaredy-cats - and I wasn`t into that at all."