Britney Spears Messes Up Lip-Syncing During Vegas Show

Britney might have to polish her lip-syncing skills after a slip-up during her Las Vegas show Piece of Me on Tuesday night. The pop diva didn't quite match her backing track to "Alien," but lucky enough a pre-recorded Britney kept the performance on par.

Hey, no biggie -- we all know Britney doesn't pride herself on live singing. Her concerts are more about the performance and the fact that, well, she's Britney.

Check the fan video below: