BERLIN — Aidan Turner and CCH Pounder have become the latest thesps to sign up for Constantin Film and Unique Features’ “The Mortal Instruments: City of Bones.”

Turner, who appears in Peter Jackson’s upcoming “The Hobbit” films and also starred as the vampire John Mitchell in BBC’s supernatural series “Being Human,” will star as Luke Garroway in Harald Zwart’s adaptation of the first book in Cassandra Clare’s bestselling fantasy book series.

Pounder, who starred in James Cameron’s “Avatar” and currently appears in the Syfy series “Warehouse 13,” stars as Madame Dorothea.

Lily Collins and Jamie Campbell Bower topline “Mortal Instruments,” the first in a planned franchise that also stars Lena Headey, Jared Harris, Robert Sheehan and Kevin Durand.

“Mortal Instruments” follows teenager Clary Fray, who discovers she is the descendent of a demon-hunting clan.

Robert Kulzer and Don Carmody are producing, with Bob Shaye, Michael Lynne and Martin Moszkowicz exec producing.

The film starts shooting this summer in Toronto. Screen Gems will release the film in the U.S. on Aug. 23, 2013; Constantin is distributing the pic in Germany.