The Jonas Brothers invade theaters this weekend with their new big-screen extravaganza, 'Jonas Brothers: The 3D Concert Experience,' and last night ET was there as Kevin, Joe and Nick surprised hysterical fans at a sold-out midnight showing of their movie in Hollywood!

"Their reaction was priceless," Nick told ET. "For us, I think, just to be able to surprise our fans is always an honor and always a pleasure, and we're so thankful that we have such dedicated fans."

The crowd went absolutely wild when the musical trio took the stage before the movie to greet them and perform a special three-song acoustic set at the El Capitan Theatre on Hollywood Blvd.

"It's a new feeling for us," said Joe. "We never felt like this before; we don't know what it feels like to have a movie coming out. It's amazing."

Tomorrow, the JoBros will appear on ABC's "Good Morning America" Weekend Edition to talk about the new movie and their "surprise theater invasion" coast-to-coast strategy!

In theaters now, 'Jonas Brothers: The 3D Concert Experience' blends footage of Kevin, Joe and Nick's red-hot Burning Up concert tour -- featuring guest performances by Demi Lovato and Taylor Swift -- with exclusive behind-the-scenes footage, off-the-wall segments, a never-before-heard song (called "Love Is On Its Way") and more!