Jimmy Fallon surprises fans at Jonas Brothers Concert

Jimmy Fallon surprised Jonas Brothers fans at their Sunday night concert.

The late night host made an unexpected appearance and took the stage at Yankee Stadium in Bronx, New York. He led the audience in a sing-along version of ‘Mr. Positive side.”

“A huge thank you to @jonasbrothers for giving me the surprise guest spot on ‘The Tour’ tour. And thanks to @yankeestadium for making it the world’s biggest karaoke party. This is one of those nights I will never forget,” Fallon posted along with a video on social media.

“I brought my boombox,” he also shouted to the crowd as he showed off his boombox, which was attached to a shoulder strap.

“Having fun yet?” he added, to cheers from the crowd.

Fallon appeared after intermission to re-introduce the group at Sunday night’s concert. It was the second date of the Jonas Brothers’ The Tour tour, which kicked off Saturday night at Yankee Stadium.

The Jonas Brothers — Joe, Nick and Kevin — play material from five different albums on tour, including their latest album this year. The album.

“It’s our most ambitious show we’ve ever put on, in the sense that building five albums in one night was a challenge that I don’t think we quite understood after we’d already put it on sale,” Nick told People of their current tour. “(But) it’s great to just go back and look at the road that has now brought us to this moment.”

The Tour includes 90 performances and goes abroad after the American part. Next up is Boston on Tuesday.

The Jonas Brothers have appeared on Fallon’s talk show, NBC’s The Tonight Show Starring Jimmy Fallon, several times. In one performance, the brothers played “Sucker” with Fallon and the Roots using classroom instruments.

The tonight show is one of several shows that paused production due to the writers’ strike, which began in early May.