Lots of different website saying Muse may perform at the apple event, all saying its very likely because of them getting U2 to perform before.
Dana Wollman - 4:59 PM Live Apple Blog
"Great acoustics too. Maybe U2 will show up again?
Or maybe Muse! If we're really lucky, we just might get another sincere/awkward finger-touch moment"
http://www.engadget.com/2015/03/09/apple-watch-spring-forward-liveblog/#!post=76429