Merkerson says she's been cast to play Martin's mother in the upcoming Marvin Gaye biopic "Sexual Healing." Her manager Bob McGowan says production begins in Luxembourg in late March.
Merkerson played Lt. Anita Van Buren on "Law & Order" from 1991 until it ended in 2010. Martin played Detective Ed Green from 1999 to 2008.
The film focuses on Gaye in the 1980s when he battled drug abuse and depression.
Merkerson spoke Monday while promoting NBC's drama "Deception," in which she plays the mother of show's lead character Johanna. She's also in the Tyler Perry-produced film comedy "We The Peeples" due out in May.