Cumberbatch is set to play Senator William ”Billy” Bulger, Whitey’s brother, in the movie after Pearce was forced to leave the project due to scheduling issues.
Billy Bulger was a career politician who claimed he had been unaware of the extent of his brother's criminal interests.
Last November Whitey Bulger was sentenced to life in prison for murder, extortion, and money-laundering at the age of 84. He’s linked to a string of murders in Boston in the 1970s and 80s.
The biopic is based on the book “Black Mass: Whitey Bulger, the FBI and a Devil's Deal.” It will chronicle the story of the infamous Boston crime king, who headed up a violent gang, the Winter Hill Gang, while simultaneously informing on his rivals to the FBI.
The movie has already started filming in Massachusetts. However the Boston Globe has speculated that part of the movie could be filmed in Northern Ireland, as they spotted IRA graffiti in some the stills released from set.
Also joining the cast is “Parks and Recreations” star Adam Scott who will play an FBI agent, as well as Joel Edgerton, Dakota Johnson, Juno Temple and Jesse Plemons. The movie is being directed by Scott Cooper.