There's no stopping Lady Gaga ... even if she falls off a piano during a live show.

While performing the song "You and I" in Houston, the eccentric singer lost her footing while stepping on a piano seat ... and Lady G went crashing to the floor. You can even hear the "Born This Way" singer say "ouch" when she hits the ground. Poor Gaga!

Like a true performer, she doesn't miss a beat.

Hear Gaga talking candidly backstage during one of her rehearsals ... after the jump.