Charlie Sheen unexpectedly showed up at a taping of Drew Carey’s Improv-A-Ganza, a new series which will begin airing on GSN in March. The actor’s appearance wasn’t just a surprise for host Carey and a whole group of comedians -- GSN had no idea he was going to be there, either.

Sheen appeared on stage during a live performance at the MGM Grand in Las Vegas, joining the cast of comedians for a segment that involves creating a story on the spot.

In the photo above, Sheen is pictured with Colin Mochrie, Carey, Greg Proops, Chip Esten, Jeff Davis and Ryan Stiles.