Tony winner Phyllis Frelich will guest-star on CSI as Gil Grissom's mother, Entertainment Weekly reports.
Frelich will appear in the Feb. 3 episode, which revolves around a murder at a school for the deaf, where Grissom's mother is a professor. Mrs. Grissom will butt heads with the newest Mrs. Grissom — Sara (Jorja Fox), Gil's wife — who works the case. It turns out Mama Grissom has another woman in mind for her son: her protégé and Gil's ex, to be played by Marlee Matlin.
William Petersen, who left the show two seasons ago, will not reprise his role as Grissom in the episode.
Frelich, who is deaf, won a Tony for her work in the 1980 Broadway production of Children of a Lesser God. The 1986 film adaptation of the play won Matlin an Oscar for her performance.
An email to CBS was not immediately returned.