Oscar winner Jennifer Hudson had sex on her mind while playing a strung-out heroin addict in new film The Inevitable Defeat Of Mister & Pete after a former junkie told her getting high was like an orgasm.

The clean-living star has never even tasted alcohol and had nothing to draw from for the part, so she visited recovering drug addicts in rehab to research her latest role.

Hudson reveals she listened to a tales of hellish stories about addiction, but still needed help in nailing her strung-out character.

The Dreamgirls star says, "I met with several different ladies and they would tell me their stories... The stories I heard were, like, unbelievable.

"(One woman) told me that one time she was going for her high and she had her baby in a book bag."

Hudson took her to one side and asked for specifics about a heroin high, adding, "She told me it was like an orgasm and I was like, 'I can do that part!'"

The actress/singer admits her back-to-back filming schedule helped too - because she was so tired after wrapping up Tv series Smash on the morning of her first drug scenes she actually fell asleep and her manager had to wake her up during a scene.