The Beastie Boys have been promoting their brand new memoir, which features stories about their historic careers as some of the most popular musicians of the last few decades. The group has been an incredible influence to a number of artists in the world and Jimmy Fallon just so happens to be a superfan. He invited Mike "Mike D" Diamond and Adam "Ad-Rock" Horowitz onto his late-night show to chop it up, discussing some funny times about the late Adam Yauch.

MCA passed away a few years ago but his memory lives on through the countless hits that Beastie Boys delivered. One of his goals was to perform "Walk This Way" with Aerosmith and Run-DMC and, though it may not have been planned, he ended up succeeding in his journey. Mike D and Ad-Rock spoke about the time MCA crashed an Aerosmith concert to play bass out of nowhere. "So the song starts, people go crazy and then Yauch runs out with this bass," says Ad-Rock. "You just look at the Aerosmith guys and they’re like, ‘Who is this guy?’ And then all of a sudden he goes up to Joe Perry and is trying to go back-to-back with him, like a rock guitar player. And Joe Perry was like, you could see him very uncomfortable and Yauch was chasing him around, running around backwards trying to play guitar."

The Beastie Boys have definitely got some more wild stories about the late MCA. Watch them recall the event below.