AMC's highly-anticipated Preacher has added yet another member to its cast, with Joseph Gilgun signing on to play the Irish vampire Cassidy. He joins a cast that already includes Ruth Negga as Tulip and Ian Colletti as Arseface. Dominic Cooper is still in negotiations to play the lead character Jesse Custer, but his deal has not been finalized at this time.

The story, based on Garth Ennis and Steve Dillon's graphic novel of the same name, follows Texas preacher Jesse Custer, who merges with a creature that has escaped from heaven, which gives him the ability to make anyone do as he commands. After learning that God has abandoned his post in heaven, Jesse goes on a quest to literally find God, along with his ex-girlfriend Tulip and Cassidy. The vampire Cassidy is more than 100 years old, but he is described by Deadline as "the most wild-ass, bestest 'bro' you'd ever want to meet." Cassidy is known for his relentless conversations that run the gamut from religion, politics, pop culture and theories on human flatulence.

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Seth Rogen and Evan Goldberg are directing the pilot episode, which was written by Sam Catlin. The writer and directors are also executive producing alongside James Weaver, Neal H. Moritz, Vivian Cannon, Ori Marmur, Ken F. Levin and Jason Netter. No production start date has been given at this time. Joseph Gilgun has been steadily working in his native U.K. for over a decade, but Preacher marks only his second U.S. gig, after the upcoming feature The Last Witch Hunter starring Vin Diesel. His previous feature credits include Harry Brown, Lockout and Pride.