HBO confirmed that the duo will replace main cast Matthew McConaughey and Woody Harrelson from the first season of the crime anthology, reported Ace Showbiz.
Vaughn is announced to portray a character named Frank Semyon, "a career criminal in danger of losing his empire when his move into legitimate enterprise is upended by the murder of a business partner."
Meanwhile, Farrell is going to play Ray Velcoro, "a compromised detective whose allegiances are torn between his masters in a corrupt police department and the mobster who owns him."
The two other leads, one of which is expected to be a prominent actress, haven't been revealed.
Nic Pizzolatto who created the show and penned the first season will write the second one. 'Fast & Furious' director Justin Lin is tapped to serve behind the lens, replacing Emmy winner Cary Fukunaga from the first season.
Production is expected to begin soon in California.