The actor joins Jeff Bridges, Ben Barnes, Jennifer Lawrence and Julianne Moore in the Warner Bros. fantasy.
The Killing Bono star also discusses his upcoming dramas The Wedding and The Words.
The Legendary Pictures project will come to theaters Feb. 15, 2013.
Pacific Rim, The Seventh Son, Paradise Lost, and Mass Effect will be featured in the studio's first standalone panel on Friday, July 22.
The Chronicles of Narnia star replaces Sam Claflin as Tom, a young exorcist apprentice to Jeff Bridges' character Spook.
The actors will play Tom and Alice in the fantasy tale being circled by Jeff Bridges and Julianne Moore.
Alex Pettyfer and Jennifer Lawrence are circling this project about an exorcist in training.
Known to U.K. readers as The Wardstone Chronicles, three actors are rumored to star, with Alex Pettyfer ditching The Mortal Instruments for another young-adult franchise.
An adaptation of Joseph Delaney's children's tome.