Samuel L. Jackson has signed on to star in Unthinkable for director Gregor Jordan according to The Hollywood Reporter. Jordan recently completed production on The Informers, an adaptation of a Bret Easton Ellis novel starring Winona Ryder, Mickey Rourke and Billy Bob Thornton which is set to open this fall. Jackson will next be seen in Neil LaBute's Lakeview Terrace, due out September 19th.