Jonny Greenwood joined Australian band ACO Underground at The Standard in Sydney, Australia on Sunday night. The Radiohead guitarist/multi-instrumentalist extraordinaire took the stage for a solo performance of “Electric Counterpoint,” a minimalist piece by American composer Steve Reich. The surprise appearance came after ACO Underground played a few songs that Greenwood had composed for them, with frontwoman Satu Vänskä welcoming him on stage as the crowd descended into a thunderous applause. You can watch a video of Greenwood performing “Electric Counterpoint” at the 2011 Sacrum Profanum Festival in Krakow, Poland above.

In addition to performing his own renditions of various pieces, Greenwood has done a good bit of composing himself. He recently released an untitled album with Polish composer Krzysztof Penderecki, which includes his works “Popcorn Superhet” and “48 Responses to Polymorphia.” Greenwood has also written the scores for the films Bodysong, There Will Be Blood and The Master.

ACO Underground are an electro-acoustic collective consisting of members of the Australian Chamber Orchestra and other musicians. They perform the music of artists like Nick Drake, Radiohead and Nirvana, as well as Vivaldi and Paganini.