Lenny Kravitz joins in
I remember when this happen and it was put on the front page of Reddit way back in the day. I thought it was cool that Lenny overheard his music and decided to join in and jam with the choir. You get to see this everyday when the actual artist shows up and plays with you.
Fly Away is probably my favorite song from his collection of songs.
BTW, he marred a Huxtable and had an member of the X-Men. Pretty cool.