Yet must Simpson bear the cross alone, while all the entertainment world goes free? Consider this:

Now-classic footage from shows like “American Bandstand” featured artists lip-synching.

Michael Jackson mouthed part of his superstar-making moment on the “Motown 25” TV show in 1983.

Whitney Houston‘s spine-chilling rendition of “The Star-Spangled Banner” at the 1991 Super Bowl was prerecorded.

And perhaps the only moments when Britney Spears did not lip-synch during her recent tour was when she said hello and goodbye to her audience.

“It doesn’t make the least bit of difference,” Dick Clark, America’s oldest teenager and the creator of the now-defunct “American Bandstand,” told The Associated Press.

“Every motion picture you’ve seen, every ‘American Bandstand’ you saw, most of all MTV you see, it’s all lip-synched,” he said. “(What’s important is) the impression you get as an audience. If you’re pleased with what you saw, who gives a hoot how it got to you?”

It never seemed to matter in the past.

We’ve all watched performances where singers dance, prance, and almost do back-flips while singing – but aren’t a bit out of breath. Or when they sing earnestly to a prerecorded ballad during a TV show. Or rap along to their own song, a la Eminem, also on a recent “Saturday Night Live.”

Producer Jimmy Jam, who’s worked with artists ranging from Janet Jackson to Usher, said he too was surprised over the Simpson incident – surprised that it was such a big deal.

“I thought everybody knew that everybody lip-synched,” he said. “I just thought when you went and saw Britney Spears, you knew that she lip-synched the whole concert. … They’re seeing a show, and to them, that’s what a show is.”

Not for everyone. R&B veteran Patti LaBelle, known for her booming voice and creative improvisations, lamented that “the whole world is so phony today so people are accepting it. People are loving phonies.”

Sounding hoarse from recent performances, LaBelle said she never lip-synchs at shows. But she’s seen plenty of it, and not just from singers with feather-light voices.

“I was surprised when I heard some of the people who were doing it,” she said. “When some of the bigger stars who can sing their butts off are using some enhancements, I’m like, why?”

Steve Leeds, a former record executive at labels such as Virgin and Universal, offers an explanation: “People want to hear what’s on the record. You’ve got to supply that expectation with whatever’s necessary. Studio wizardry is definitely part of a live music show today.”

Sometimes, performers just plain lip-synch. Other times they add an extra vocal of the song, and sing along to it so their voices sound fuller. Then there’s live help – background singers to make the star’s voice sound stronger.

And sometimes, they just want it to sound perfect.

“There’s more of a premium of getting it right,” said Jam. “Whitney, when she did the national anthem, which was the greatest national anthem that we ever heard, what we heard over the air was prerecorded. The reason it was prerecorded was, that was a moment that no one wanted any mistake. They didn’t want any feedback, they didn’t want any technical difficulties … and it was great.”

While Taylor Hanson of the group Hanson acknowledges that not all lip-synched performances are evil, he complains that record companies today are manufacturing artists who can’t perform live even if they wanted to.

“There’s so many great bands who are performing, and singing their guts out every night, and the prevalence of artists being represented … and saying, ‘Hey everyone does this, everyone sings to track,’ I just think it’s lowering the standard,” he fumed. “It’s totally insulting to so much great music out there.”

But P. Diddy says the practice has become standard, especially in an era where it’s become more common for entertainers to do everything but juggle onstage.

“So many people at times have used backup tracks. I just think (Simpson) was the first one that had a mishap on it. I’ve heard her sing live. I don’t think she’s doing no Milli Vanilli,” he said, referring to the infamous duo that didn’t even sing the vocals they were lip-synching to.

“That’s the way the ball bounces,” Diddy said. “I don’t think she’ll be the last one to sing along to a track.”