CBS announced that it has booked Jason O'Mara (Vegas) in a recurring role for Season 5 of The Good Wife. The network also released the first set of images fom the upcoming season premiere.

O'Mara will play Colin, an aggressive Irish attorney, who has a decade of successfully defending gang members and crime families behind him. Colin joins the the corporate law firm Lockhart/Garnder and struggles with fitting in with the firm's more conservative culture.

The Good Wife has had a host of recurring characters played by high profile stars featuring the likes of Michael J. Fox, Matthew Perry, Maura Tierney, Nathan Lane, Gary Cole, and Amanda Peet.

O'Mara was starring in Vegas -- but CBS cancelled the show earlier this year.

Stills from the first episode, Keeping the Secret, were also released by CBS.

Here's the official description for the fifth season premiere:

"'How to Begin...' - Alicia must focus on the firm's efforts to prevent the execution of a convicted murderer while she secretly plans her exit from the firm with Cary. Meanwhile, Eli helps Peter assemble his staff in the governor's office, on the fifth season premiere of THE GOOD WIFE, Sunday, Sept. 29 (9:00-10:00 PM, ET/PT) on the CBS Television Network. Jeffrey Tambor guest stars as Judge Kluger; Melissa George guest stars as Marilyn, Peter's ethics counsel; Ben Rappaport guest stars as lawyer Carey Zepps; and renowned defense attorney Barry Scheck guest stars as himself."

Alicia's decision to leave Lockhart/Gardner stirs a "bloodbath" in Season 5.

The Good Wife Season 5 premieres on Sunday, Sept. 29 at 9 p.m. ET on CBS.

Watch the teaser for Season 5: