Jimmy Fallon Joins Jonas Brothers Onstage, Leads Singalong at New York Concert

Jimmy Fallon made a surprise appearance at the Jonas Brothers' concert at Yankee Stadium in New York City.
Fallon led the crowd in a singalong of The Killers' "Mr. Brightside," playing a boombox.
The concert was part of the Jonas Brothers' 90-date world tour across 20 countries.
The tour features songs from the band's six albums, including their latest release "The Album."
Fans expressed excitement on social media over Fallon's unannounced guest appearance.