Jennifer Jason Leigh will step into the Tony Award-winning Broadway staging of David Auburn's Proof Sept. 11, replacing Mary-Louise Parker, who originated the role of Catherine, the troubled daughter of a math genius.

Leigh's most recent Broadway appearance was as Sally Bowles in Cabaret. Parker, who took home the Tony Award for Best Actress for her performance as the 25-year-old Catherine, leaves the Pulitzer Prize-wining play Sept. 9. A national tour commences this fall, not with Parker, beginning with a resident run at the nonprofit Seattle Repertory Theatre.

Patrick Tovatt and Tony nominees Johanna Day and Ben Shenkman are currently in the Broadway production, at the Walter Kerr Theatre. Daniel Sullivan won a Tony Award for his direction. He'll also helm the tour.

There is no word yet whether Day (who plays Catherine's sister) and Shenkman (who plays suitor Hal) will continue in their roles, which they originated at Manhattan Theatre Club in 2000, along with Parker and Larry Bryggman (who played the father and left the Broadway mounting recently). Tovatt will continue in the father role. Additional casting will be announced, according to the producers.

Leigh is known for playing troubled, fascinating and searching women, and Proof will be an extension of that. On one level, the play concerns family legacy, and the idea of facing the genius — or illness — passed down from parents. Leigh's other theatre work includes Picnic (Ahmanson Theatre) and Sunshine (Circle Rep). She is better known for her film work, including the current "The Anniversary Party," which she co-wrote and co-directed with Alan Cumming, her Cabaret co-star. Her other films include "Last Exit to Brooklyn," "Miami Blues," "Mrs. Parker and the Vicious Circle," "Georgia," "eXistenZ," "Washington Square," "Kansas City," "Short Cuts," "The Hudsucker Proxy," "Delores Claiborne," "Single White Female," "Rush," "A Thousand Acres," "Fast Times at Ridgemont High" and "The Big Picture." Her next film is "The Road to Perdition."

Proof tickets are $24-$69. The Walter Kerr is at 219 W. 48th Street. For information call (212) 239-6200.