LOS ANGELES (June 12) -- Dermot Mulroney has filed for divorce, seeking to end his nearly 17-year marriage to Catherine Keener .

The actor cited irreconcilable differences and asked for joint custody of their 7-year-old son, Clyde, according to documents filed Friday in Los Angeles County Superior Court.

The two, who appeared in the 2001 film "Lovely & Amazing," were married in November 1990 and separated in May 2005, the documents said. An after-hours e-mail to Keener's publicist was not immediately returned.

Mulroney has starred in such films as "My Best Friend's Wedding," "The Wedding Date," and "Georgia Rule."

Keener, who has two Oscar nominations for supporting roles in "Capote" and "Being John Malkovich ," has also appeared in "The 40-Year-Old Virgin" and "The Ballad of Jack and Rose."