The Jonas Brothers Bring Out Kirk Franklin, Jimmy Fallon, and Big Rob at First Shows of New Tour

Fallon surprised fans when he hopped onstage at the Aug. 13 show and joined the brothers in singing “Mr. Brightside” by The Killers. “How would you all like to be in the world’s biggest karaoke party for two minutes?” he asked the crowd, per one video.

He commemorated the experience on Twitter later that night, writing, “Huge thanks to @jonasbrothers for giving me the surprise guest spot on ‘The Tour’ tour. And thank you to @yankeestadium for turning it into the world’s biggest karaoke party. This is one of those nights I will never forget.”