System of a Down's Serj Tankian is collaborating on Prometheus Bound, a new rock-based musical from Spring Awakening lyricist and book writer Steven Sater. Tankian hinted at the collaboration to Rock Daily back in August. The musical is now in the workshop phase at Cambridge's American Repertory Theatre, with a full production planned for the 2009-10 season. Based on the Greek myth of Prometheus, Gossip Girl's Patrick Heusinger has been cast as the mortal who steals fire from the Gods. "I stayed very faithful to the ancient Greek text," Sater said. "Of course, we're transforming it and it's going to have an underlying concept for the show. But we just opened it up with music. The chorus, what they sing is so ethereal and beautiful and melodic, and it's set against wailing rock anthems that come from Prometheus and Oceanus and the other characters." The score will comprise of 12 songs.