If Ashlee Simpson's (search) stomach was upset Saturday night, imagine how she's feeling now. The 19-year-old singer was busted for a "Saturday Night Live" lip-synch gone awry. Her manager-father said Monday his daughter used the extra help because acid reflux disease had made her voice hoarse.

"Just like any artist in America, she has a backing track that she pushes so you don't have to hear her croak through a song on national television," Joe Simpson told Ryan Seacrest (search) on Los Angeles radio station KIIS-FM. "No one wants to hear that."

And he said she's never used the extra help onstage before.

"The whole situation was a bummer," Ashlee Simpson said in an interview on MTV's "Total Request Live."

Simpson had performed her hit single "Pieces of Me" without incident earlier on "SNL." When she came back a second time, her band started playing and the first lines of her singing "Pieces of Me" could be heard again.

She was holding her microphone at her waist at the time. Simpson looked momentarily confused as the band plowed ahead with the song and the vocal was quickly silenced.

A flustered Simpson made some exaggerated hopping dance moves, then walked off the stage.

She told "TRL" that she and her band didn't know what to do. "I think all of us went into a state of shock," she said.

The incident exposed what many consider an obvious secret: that some singers who appear onstage aren't singing live at all, or at least have their voices augmented by backing tracks. And it's happened before on "Saturday Night Live," too, executive producer Lorne Michaels told the Associated Press.

"She was mortified and in her dressing room, but (producer) Marci (Klein) got her to come out for goodnights and explained that it wasn't the end of the world. It wasn't her fault," Michaels told AP Radio.

"Every artist that I know in this business has had vocal problems at some time — from Celine on down," said Joe Simpson, also father of Jessica Simpson (search). "So you've got to do what you've got to do."

He said it was his decision to use the tapes when it became apparent that acid reflux disease had swollen Ashlee's vocal cords.

Said Michaels: "If she were a more seasoned performer then I think that she would've taken charge and said, `No, let's start this over again.'"

To add to Ashlee's indignity Monday, eBay.com was auctioning off her private cell phone number, which it said had been inadvertently, and briefly, posted on her Web site.

Ashlee told NBC that the drummer hit the wrong switch on "Saturday Night Live" and played the wrong music track. She insisted he's a good friend and a good drummer and she wouldn't dream of firing him.

Simpson said musicians frequently sing along with pre-recorded music, called backing tracks, for vocal support.

She also says comparisons to Milli Vanilli are unfair. She says Saturday was the first time she had ever used a backing track.

The singer said she hopes her fans know when they come to her concerts they're hearing her live.