"Priest" director Scott Stewart has updated the casting status of his upcoming vampire film, which recently signed aboard Christopher Plummer.

Stewart announced through Twitter that Plummer will play "Monsignor Orelas, the leader of our Orwellian Church State."

In addition, Stewart said actor Alan Dale ("Indiana Jones and the Kingdom of the Crystal Skull") is signed on as Monsignor Chamberlain. The New Zealand actor recently wrapped work on the Guillermo del Toro scripted "Don't Be Afraid of the Dark."

"Priest," based on a graphic novel by Min-Woo Hyung, is set in a world dominated by war between man and vampire. It follows a warrior priest (Paul Bettany) who turns against the church to hunt a band of vampires who have kidnapped his niece.

Cam Gigandet, Maggie Q, Karl Urban, Stephen Moyer and Lily Collins co-star.

The film opens in theaters Aug. 13, 2010.