Ashlee Simpson performed on Saturday Night Live this weekend, and managed to make the third word in the show's title decidedly redundant. Kid sister to pop package Jessica, Ashlee has been criticised in the past for her flat live vocal performances.

This time she belted out her hit Pieces of me inch-perfect on stage with her band. After giggling to the applause, when she returned to the stage for her next track Autobiography, things went a little awry.

Even as she took her position, the first track started playing again, words and all. As she awkwardly looked around while 'her voice' from Pieces… played on, the studio audience, as well as the world watching the popular television show, burst into raucous laughter.

The 'manufactured MTV darling', said the Boston Herald, has been exposed as a lip-syncing fraud.

The band tried hard to suddenly look like they were rocking appropriately to the music, a task admittedly difficult when trying to play a softer song. A clueless Ashlee tried to gyrate painfully to the music, with an impromptu hoedown, and, after 35 seconds of the humiliaton, scampered off stage.

She later blamed her musicians for playing the wrong song, while her record company Geffen blamed a "computer glitch".

It was probably best summed up by Jude Law, guest host for the night. Standing next to a disgracefully embarrassed Ashlee, he smiled gamely and said: "What can I say, folks? Live TV."

Photograph: Getty Images