Update (1:15 p.m. EDT): The Wall Street Journal tweets this distressing denial from a Radiohead spokesman about the performance: "we can officially say its not happening." Too bad for anybody who's already started faking an illness to take the afternoon off. CNN producer Vaughn Sterling points out on Twitter: "At this point if Radiohead *doesn't* play at OccupyWallStreet we are going to see protests of a whole different order of magnitiude"

Original: The band was in town for a concert anyway, so Radiohead has decided to join the other big names who have lent their support to the Occupy Wall Street protesters by planning a performance in Zuccotti Park at 4 p.m. The protest's official web site calls it a "surprise show," which it was until about an hour ago. Anonops, a website associated with Anonymous, already has plans in place to stream the show in case you can't make it. Michael Moore and Susan Sarandon are great and all, but this visit going to be a lot more fun. And as Jon Stewart pointed out, the crowd already looks like they're at Bonnaroo.