Tributes to Michael Jackson have come by the barrelful in recent weeks, but rarely from a source as unexpected as Pearl Jam.

During Pearl Jam's gig at London's Shepherds Bush Empire Tuesday night, the Seattle alt-rockers treated 2000 lucky fans to a pair of surprises: a brand new acoustic song and a cameo from Rolling Stones guitarist Ronnie Wood, who joined the five-piece onstage for a rousing rendition of Bob Dylan's "All Along the Watchtower." Watch below!

Look below, dear Pearl Jam fans, and find one of nine pieces of art to be featured on the alt-rock band's September release, Backspacer. This image -- exclusive to SPIN.com -- is part of a collaboration between the band and graphic artist Tom Tomorrow.

Pearl Jam released "The Fixer," the first single from their September release, Backspacer, to radio stations and their MySpace page this morning. Listen here.

Pearl Jam have announced a handful of North American shows behind their new album, Backspacer, out Sept. 20.

Two of hip-hop's biggest stars, Eminem and Jay-Z, took the stage earlier this week for a rare joint performance in L.A. -- and the two were making headlines on their own, as well.