Green Day

However, on Sunday afternoon, Green Day released a statement announcing that Armstrong would be entering treatment for substance abuse. The brief statement added that "We would like everyone to know that our set was not cut short by Clear Channel and to apologize to those we offended at the iHeartRadio Festival in Las Vegas. We regretfully must postpone some of our upcoming promotional appearances." The band had been slated for a number of TV appearances this week, as well as a performance for KROQ/Los Angeles. Green Day's new album Uno! arrives in stores tomorrow.

Armstrong was recently hospitalized in Italy for undisclosed reasons, forcing Green Day to cancel a show overseas. He will soon appear on NBC's The Voice as a coach, but MTV News reports his contributions were filmed over the summer.

P!nk

Saturday night featured a surprise appearance from Prince, who played a pair of duets with Mary J. Blige, as well as sets from Taylor Swift, Aerosmith, Linkin Park and Pitbull. Blige and Prince covered "Sweet Thing" by Rufus and Chaka Khan before playing a version of Prince's own "Nothing Compares 2 U." My Chemical Romance singer Gerard Way performed alongside EDM star deadmau5, as Way appears on the mouse-headed DJ's new single "Professional Griefers.

Videos, photos and more can be found at www.iheartradio.com/vegas.