Muse will be supporting U2 on at least one date of their 14-city "360º" Tour. The following has been published on the IZOD Center's (a venue in New Jersey which U2 will be performing at in September) website.
Beginning June 30th in Barcelona, the tour will visit 14 cities across Europe before it launches in North America in early September.The tour features an innovative 360° design which affords an unobstructed view for the audience. U2 360° marks the first time a band has toured in stadiums with such a unique and original structure [...]
Although this has not yet been announced by Muse's management, its appearance on the IZOD Center's website can almost be considered confirmation. It is not yet clear if Muse will be supporting U2 on their European / UK tour. Share your frustration / joy in the comments.