Gloria Reuben has joined Reasonable Doubt, teaming with Samuel L. Jackson and Dominic Cooper for the indie crime thriller. Reuben will play world-weary Detective Blake Kanon in the South Creek Pictures pic, which centers on an Assistant D.A. who becomes obsessed with a man found not guilty of a hit and run. Peter Howitt directed from a script by Peter Dowling. Reuben plays Elizabeth Keckley, Mary Todd Lincoln’s dressmaker and confidante, in Steven Spielberg’s Lincoln; she was at the White House last week for a private screening. She also appears in the upcoming comedy Admission with Tina Fey and Paul Rudd. The ER veteran also will appear in a five-episode arc on the third season of TNT’s Falling Skies, on which Spielberg is an executive producer. Reuben is repped by APA and manager Estelle Lasher.