We were there last night when the Jonas Brothers thrilled fans by performing at the first showing of their new 3-D concert flick at the El Capitan Theatre in Hollywood, California. Before the midnight movie started, Joe, Kevin, and Nick took the stage and sang three songs.

We've got footage of them performing, as well as fan reaction to the surprise appearance. And in case you're wondering, even without the live performance, First Fans declared Jonas Brothers: The 3D Concert Experience "fantasic," "amazing," and "the best movie ever!"