Mariah Carey Lip Sync BET Awards 2013 and American Idol [VIDEO], Mariah Carey and Miguel Beautiful Singer Lip Sync Scandal

Mariah Carey American Idol star unleashed a flurry of speculation that she was lip-syncing during her performance of her hit duet with Miguel "#Beautiful" at the 2013 BET Awards.

Mariah Carey faced similar accusations about her performance during the finale of American Idol.

"Is it me or is Mariah lip-syncing?" Aliyah Harmony tweeted with the #MariahBET hashtag.

 "I thought my TV was lagging a few seconds," F_Beezus responded.

According to the Los Angeles Times, some suggested the upper register notes she once was famous for hitting may be getting beyond her reach.  "#MariahBET is a legend," Nucktorious tweeted, "but that high register died back in 99."

Watch Mariah Carey American Idol star Lip Sync:

Mariah Carey husband Nick Cannon told E!Online before the show that there are no smoke or mirrors in her performances.

"My wife is a perfectionist and clearly because she's done it right all her life," Cannon said. "So she actually puts a lot of work into these performances. There's no management helping make decisions. Everything you see is all her, whether it's a collaboration when the lights hit, how she enters, she's doing all of that."