Nobody paid much attention to lip-synching until a pop group called Milli Vanilli (search) won a Grammy for songs that turned out were actually sung by someone else.

The 1990 scandal spelled the end of the duo's career and almost made lip-synching (search) a thing of the past completely. But with more performances these days hinging on dazzling staging, it's hard to carry a tune while dangling upside down or holding a live snake.

At TV awards shows like the Video Music Awards (search) and the American Music Awards (which aired Sunday), fancy dance moves, acrobatics and special effects seem to take precedence over a simple live song. Enter lip-synching — to one's own vocals, of course — which has become a more common practice because of all the theatrics.

"The awards shows are all about the stage and the show and amazing spectacles," said J.R. Griffin, reviews editor at E! Online. "They're about seeing the celebrities — what they'll say, what they'll wear. Music takes a backseat."

That was the case at the VMAs in August. One of the most elaborate numbers featured a sexily clad Beyonce Knowles being lowered to the stage upside down, then dancing her way through a fast-paced number. Though Beyonce is a talented singer, there was buzz afterward about her lip-synching.

"How hot is Beyonce?" syndicated columnist Liz Smith wrote. "So hot that nobody seemed to mind — or notice — that she lip-synched her steamy number at the MTV Video Music Awards."

Entertainment Weekly music critic David Browne was amazed that Beyonce didn't try to hide that she wasn't belting out the tune. "There wasn't even a pretense that she was doing anything but dancing to her own track."

But pop stars like Beyonce and Britney Spears haven't given up the illusion of singing. They're often outfitted with microphone headsets, and they do sing some of the song over the taped version.

"With Britney Spears, for instance, it seems like she's lip-synching, but then she'll sing 'Hey' or 'Come on, everybody!'" Griffin said.

When asked about lip-synching in a recent television interview, Britney said there's usually a tape of her voice and the voices of backup singers playing as she performs, but she's "not technically lip-synching" because she does sing along.

The practice of lip-synching has become common enough that the Grammy awards has a rule against it — except in rare cases, according to Browne.

"Certain shows like the Grammys pride themselves on banning lip-synching," he said. "Other shows are a little more open to the idea. The whole point of the Grammys is really seeing people sing."

American Music Awards publicist Paul Shefrin said the show doesn't have rules against lip-synching.

"There is no policy," Shefrin said. "The artists choose their route. It's up to them as to how they want to present themselves. Sometimes the physical movement of the act makes it difficult to mike it live."

Lip-synching on televised shows has a history dating back to the 1950s when "American Bandstand" went on the air, but it's become more sophisticated with new technology.

"It's gotten so advanced that you can sing part of a song live and the lip-synched track will kick in as soon as you stop," Browne said. "It actually is hard to tell because it goes back and forth within the same song."

For many of these shows, it comes down to what works best on TV. Most people still remember Britney prancing around with a huge snake draped over her shoulders at the 2001 VMAs, while the song she was performing is harder to recall.

"It's all just theatrics," Griffin said. "You've got people hanging upside down. They'd have to be a superhero to be able to sing upside down."

But do audiences suspect their favorite stars are sometimes mouthing the vocals over a tape — and do they mind?

"It's not good," said college sophomore Sara R., 19, of Newark, N.J. "They're making it look like they're singing to throw people off, but really they're not."

But there's a different standard for television, which is how awards shows can justify the lip-synching acts, according to Griffin.

"The producers want to put on a good show and they're willing to bend the rules a little to get what they need," he said.

Admittedly, it isn't easy to perform complicated dance moves while hitting the high notes.

"If you're dancing, you're out of breath," said music fan Lauren Crocker, 19, of England. "You can't sing."

But no matter how much razzle-dazzle goes into the performance, some would rather have singers exercise their vocal chords than their bodies.

"Some of them can't sing live," said Bronx resident Kindu Wilkins, 40, as he shopped in the Virgin Megastore in Manhattan. "That's where the travesty is."