Lisa Bonet will guest star in a Season 4 arc for "Ray Donovan," Showtime confirmed Thursday.

"Bonet will play Marisol, a dangerously unstable woman with a damaging secret," the cable-television network said in a press release announcing the casting of "The Cosby Show" and "A Different World" alum.

The show is currently in production in Los Angeles. It will return with new episodes later this year.

"Ray Donovan" stars Liev Schreiber as the titular L.A. professional fixer, "the man called in to make the city's celebrities, superstar athletes, and business moguls' most complicated and combustible situations go away."

It co-stars Paula Malcomson, Eddie Marsan, Dash Mihok, Steven Bauer, Katherine Moennig, Pooch Hall, Kerris Dorsey and Devon Bagby.