Renée Zellweger has signed on to star in and produce Piece of My Heart, a big-screen biopic on late rocker Janis Joplin. Filming is expected to get underway in early 2004 after Zellweger wraps the sequel to Bridget Jones's Diary. In other casting news, Angelina Jolie is in talks to play Catherine the Great in Disney's upcoming historical epic Love and Honor.