Actor Kevin Zeggers has been cast as Alec Lightwood in the upcoming film adaptation of Cassandra Clare’s City of Bones. 

City of Bones is the first novel in the series, The Mortal Instruments. 

Alec Lightwood is the brother to Isabelle Lightwood, who is set to be played by Jemima West. Alec also has feelings for Jace Wayland and later Magnus Bane.

Zeggers joins main characters Lily Collins as Clary Fray and Jamie Campbell-Bower as Jace Wayland. Also cast is Lena Headey, Jared Harris, Kevin Durand, and Robert Maillet.

City of Bones follows teen Clary Fray, who discovers she is a descendant of a line of Shadowhunters, an order of half-angel warriors who protect the world from demons. The rest of the characters include her best friend Simon, who is in love with her, while she has feelings for fellow shadowhunter Jace Wayland, who also may or may not be her brother, and siblings  Isabelle and Alec Lightwood, with Alec Harboring feelings for Jace as well.

Screen Gems is producing the adaptation with Harald Zwart directing.

The film is scheduled for release on August 23, 2013.