Canadian actor Taylor Kitsch, who played Gambit in X-Men Origins: Wolverine is also expected to sign on for the project.
The first series of True Detective, co-starring Matthew McConaughey and Woody Harrelson on the hunt of a serial killer in Louisiana, was a critical and popular hit, winning five Primetime Emmy awards earlier this year.
The new season will tell the story of "three police officers and a career criminal (who) must navigate a web of conspiracy in the aftermath of a murder," HBO said in a statement on Tuesday.
Farrell will play Ray Velcoro, a compromised detective whose allegiances are torn between his masters in a corrupt police department and the mobster who owns him.
Vaughn meanwhile will play 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.
- WENN