UPDATE - 11/11@4:29PM: Geddy just finished up his performance of The Who's The Seeker. Here's a photo that was posted to Instagram, along with this TwitPic.

The Who will be celebrating their 50th anniversary with a The Who Hits 50! world tour that kicks off later this month and runs through next year. Before the tour begins, the band will be hosting a benefit concert of Who music in aid of the Teenage Cancer Trust which takes place tomorrow at the O2 Shepherds Bush Empire in London, England. The Who's house band will be joined onstage to perform Who classics by a number of famous artists including Rush's Geddy Lee. Also appearing will be Pearl Jam's Eddie Vedder, Liam Gallagher, Ricky Wilson from the Kaiser Chiefs, Manic Street Preachers' James Dean Bradfield, The Strypes, Brody Dalle, Tom Odell, Amy Macdonald, Andy Burrows, Rizzle Kicks and more. The Who posted a gallery of photos from rehearsals to their Facebook page a few hours ago including a couple with Geddy in them (thanks Eric at Power Windows). There's one of Geddy and Eddie Vedder, and another with Geddy playing his bass. It's not known what Who song(s) Geddy Lee will perform, but Rush included The Who's The Seeker on their 2004 covers EP Feedback, so that is one of the likely possibilities.