Watch Billy Joel, JK Simmons and Fallon’s surprise doo-wop performance

The Internet can’t stop talking about Billy Joel’s guest appearance on The Tonight Show on Wednesday (January 7) because of the impromptu performance that took place during the commercial break!

The adorably rough start, Simmons totally nailing the bass parts, Billy Joel’s still-incredible riffing – it’s a performance that ranks among our all-time favorite Fallon moments.

Of course, with an opportunity such as this, Fallon dusts off his Mick Jagger impersonation and brings it out in full force as he joins in on the singing with Mr. Joel.

“The crew’s going, ‘You know you’re supposed to be on stage now, ‘ and I’m like, ‘Wait a minute, ‘” Joel said.

Joel also announced that he will add another show to his record-setting run at Madison Square Garden on July 20. “I would’ve kept going”.

During the actual broadcast of “The Tonight Show”, Joel and Fallon sat down for an interview together and then sang a cover of the classic Rolling Stones hit song “Beast of Burden”.

The video of the Joel and Fallon duet just got released on Youtube and you can watch it below.