Cromwell, 64, filed a dissolution of marriage petition in Superior Court on Tuesday citing unspecified irreconcilable differences as the reason for the split.
The couple married May 29, 1986, and separated Oct. 31, 2004, according to the petition. They had no children.
Cromwell, who currently portrays George Sibley on the HBO series "Six Feet Under" (search), was nominated for a supporting actor Oscar for his role as Farmer Hoggett in the talking pig movie "Babe" (search).
His other credits include "Angels in America," "Space Cowboys," "The Green Mile," "The General's Daughter" and "Snow Falling on Cedars.
Julie Cobb, the daughter of late actor Lee J. Cobb, played Jill Pembroke on the television series "Charles in Charge" in 1984 and 1985 and she's appeared on the TV shows "Star Trek," "ER" and "The Brady Bunch."