Madonna performed the best song off her new album Rebel Heart last night, with a little assist from Taylor Swift. At the iHeartRadio Awards—which consistently lures the biggest names in music—Madge took to the stage for a stirring rendition of "Ghosttown," while Swift accompanied her on acoustic guitar. Surprisingly Swift didn't sing, which at times had the surreal effect of making her seem like just another member of Madonna's band, especially when the pop star moves to the front of the stage leaving TSwift in the background and out of focus. But when Swift rejoins Madonna at the foot of the stage for the song's emotional climax, you're reminded that oh yeah, that's Taylor Swift.