July 10 [16:00 EDT] -- Ian Astbury, former frontman for the late 80s rock band The Cult, gave a surprise performance Wednesday night at L.A.'s Viper Room with goth-rockers Masters of Reality.

Astbury has been holed up in the California desert at Monkey Studios, writing and arranging new music for a forthcoming album with producer and Masters' lead singer Chris Goss.

Astbury joined Goss' band on stage during a show to promote the Masters' new release, "How High the Moon." The album features live recordings from two performances at the Viper Room, including a guest vocal from Stone Temple Pilot's Scott Weilend on "Jindalee Jindalie."

Astbury jumped onstage before a sold-out crowd and sang the Doors classic, "Riders On The Storm."

His first solo record is slated for release early next year.