Farrell will play a detective under the thumb of a mobster and Vaughn a career criminal in the award-winning show.
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.
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 last year.
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."
- nzherald.co.nz with AFP