System Of A Down frontman Serj Tankian has enlisted Tom Morello for a new EP and Shirley Manson for a musical.

Tankian released his digital only Imperfect Remixes EP today through Serjical Strike/Reprise Records on iTunes. The first track ‘Goodbye - Gate 21 (Rock Remix)’ features RATM and Audioslave guitar-twiddler Tom Morello. The four-track EP features remixes of songs from his most recent solo album Imperfect Harmonies.

Tankian has been a very busy boy of late, also writing a musical called Prometheus Bound with Tony and Grammy award-winning lyricist and playwright Steven Sater.

The first track released from the rock musical is called ‘The Hunger’ and features Garbage’s Shirley Manson on vocals. It’s available on iTunes from today with all profits going to Amnesty International, Undercover reports.

System Of A Down are also back on tour, hitting up the U.S. and Canada with seven shows in May.