Mick Jagger is three times older than Taylor Swift, but he'll probably be dancing rings around her tonight when she joins The Rolling Stones on stage in Chicago.
On Friday, Las Vegas reporter Robin Leach tweeted that Katy Perry would join the Rolling Stones onstage during their show at the MGM Grand Arena in Las Vegas on Saturday. On Saturday, the Stones themselves confirmed it, and that evening, Katy did just that, duetting with iconic frontman Mick Jagger on the Stones' classic "Beast of Burden."