Britney Spears heard a heckler loud and clear at her Las Vegas residency show Piece of Me on Wednesday night and shot right back at him.

As she was dancing and about to start a song, a man’s voice can be heard calling Spears a “fat b-tch.” She wasn’t going to ignore him and fired back by saying into her microphone “f—king a—hole!”

TMZ’s video shows the man surprised she heard him say it, replying “She heard me!” after she yelled back at him.

Spears then doesn’t miss a beat and launches right into her next song. Her critics, who condemn her for lip syncing, will be surprised to know her mic was on when she quickly hurled an insult back to the heckler, meaning she was live singing.

Due to popular demand, Spears extended her residency at Caesars Palace last year.

image via Chiva/INFphoto.com