ER actress Maura Tierney has filed for divorce from her husband of 13 years.
The actress, who also starred on the sitcom NewsRadio, cites irreconcilable differences with her husband, actor Billy Morrissette, in court papers filed in Los Angeles.
Tierney, 41, and Morrissette, 43, have been separated since March 7, according to the papers. They have no children.
Tierney, who plays Abby Lockhart on ER, told PEOPLE in 2004 that the medical skills she learned on the show have come in handy: She once diagnosed Morrissette's appendicitis. "He had localized pain in his lower right abdomen and a fever," she said. "He was also diaphoretic (perspiring). I said, 'I really think you need to go to the doctor.' The surgeon said it might have burst if we had waited. And the nurse let me help draw his blood."
Tierney has also appeared films including Primary Colors, Liar Liar and Welcome to Mooseport.
Morrissette has appeared in the movie Scotland, Pa., which he also directed, and on Mad About You, Party of Five and Diagnosis Murder.