Fallon Explains Hilarious U2 Stage Cameo: 'It Almost Didn't Happen'

'Tonight Show' host recalls how Bono's bad memory almost left him stranded in audience during band's Madison Square Garden show

U2 recruited Jimmy Fallon and the Roots for surprise cameos for their Wednesday night show at New York's Madison Square Garden. "It was an unbelievable experience," the Tonight Show host enthused during Thursday's episode. "I'll never forget it. But it almost didn't happen."

Fallon's hilarious spot involved the comedian pretending to be a random fan in the crowd, holding a sign that read "singer with a broken finger." Bono eventually pulled Fallon onstage to perform "Desire," delivering a spot-on impression of the U2 frontman – down to the opening grunt. But as Fallon explained on The Tonight Show, Bono got sidetracked and almost left his guest stranded in the audience. 

"Bono never does bits with comedians, so he's just doing Bono," Fallon recalled. "He forgets that I'm there! This is real. So he picks someone random out of the audience, and they go onstage. And I'm like, 'Uhhhh, singer with a broken finger!' So he's doing a bit with this girl, and she's a fan, and they're meerkat-ing. And the thing's going on the web. And I'm going, 'What happens?' I'm just gonna wait it out. I'll do my song, and then the Roots do their song. Then someone behind me goes, 'Put your sign down!'. . . Someone's gonna throw a beer at me, and I'm gonna be escorted by security. I'll be getting into the cop car, and I'll hear the Roots playing with U2."

U2 guitarist the Edge later reminded Bono of the mistake, and the rest is viral video history. "It was one of the greatest nights of my life," Fallon said. 

"I'm a big fan of Irish people that fall down and hurt themselves," Fallon joked during his U2 performance. "So you're like a mentor to me, brother. Edge, what you did a couple of weeks ago falling off the stage was classic, brother. I'm happy to be a part of the club."

The performers all suffered injuries in recent months. Fallon was hospitalized earlier in July after he fell down in his house and nearly ripped off his finger. The Edge took a tumble into the audience during the opening night of the band's Innocence + Experience tour, and U2 were forced to cancel a week-long run of shows on The Tonight Show in November after Bono's devastating bike accident