Kristen Stewart to Play Joan Jett in New Movie

Twilight star Kristen Stewart will be belting out her own rock tunes when she plays Joan Jett in upcoming biopic Runaways.

The actress, who showed off her singing skills while performing karaoke with Twilight co-star Robert Pattinson in Japan last month, insists fans will be able to hear her voice on the soundtrack for the new film, which chronicles the success of Jett's all-girl band.

She says, "If it's not going to be Joan, it's going to be me."