Scott Cooper’s Black Mass has added another to it’s increasingly impressive flock.  Johnny Depp (Pirates of the Caribbean) has already signed on as the infamous Boston mobster Whitey Bulger.  The role of the FBI agent chasing him is to be played by Joel Edgerton (Warrior, Zero Dark Thirty).  Now, according to Variety, Guy Pearce (Memento, L.A. Confidential) is set to join their ranks as William Bulger, a Massachusetts politician and brother of Whitey.

William Bulger, the Massachusetts senator and President of the University of Massachusetts, was forced to resign after refusing to testify in a congressional hearing about his brother in 2003.  Guy Pearce, who thrives in morally ambiguous roles, seems an ideal choice for the part.

Scott Cooper (Crazy Heart, Into the Furnace) is writing and directing.  Black Mass is the first Whitey biopic making it into production, but there’s another on its way from Ben Affleck and Matt Damon.  The film is slated for release in 2015.