Liquid Tension Experiment is an instrumental progressive rock/metal project consisting of Dream Theater members John Petrucci (guitar), Jordan Rudess (keyboard), and Mike Portnoy (drums), as well as progressive rock icon Tony Levin (bass, Chapman stick) of King Crimson. The combo was formed as a side project to Dream Theater in 1997. Rudess was asked to join Dream Theater largely because of the success of the Liquid Tension Experiment; Mike Portnoy mentioned it in the introduction of the "Liquid Drum Theater" instructional DVD and in the Score Documentary. Jordan Rudess had previously declined the offer to join in 1994, instead becoming a member of the Dixie Dregs.