Long-gesting crime drama secures second lead.

Aussie actor Joel Edgerton (‘The Great Gatsby,’ ‘Zero Dark Thirty’) has closed a deal to join Johnny Depp on the cast of the Barry Levinson-directed ‘‘Black Mass,’ reports Deadline.

Based on the book ‘Black Mass: The True Story of an Unholy Alliance Between the FBI and the Irish Mob’ by Dick Lehr and Gerald O’Neill, the crime thriller tells the true story of Whitey Bulger, the brother of a state senator and the most infamous violent criminal in the history of South Boston, who became an FBI informant to take down a Mafia family invading his turf. However, after the FBI closed in on their targets, they double-crossed Bulger and ultimately prosecuted him, along with his partner in crime and the original FBI agent working with him.

Edgerton will be taking the role of John Connolly, an FBI agent who also happened to be a childhood friend of Bulger’s.