Mariah Carey Lip Sync at BET Awards Claimed by Tweeters (Video)

Mariah Carey's appearance at the BET Awards Sunday night sparked a whole new round of Twitter claims that accused the singer of lip-syncing her entire performance.

Carey appeared with singer Miguel and rapper Young Jeezy to perform her hit "Beautiful," but something definitely seemed off, viewers noted.

Nick Cannon, Carey's husband, spoke with reporters outside before the show and promised that his wife would wow them with her performance.

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"My wife is a perfectionist and clearly because she's done it right all her life. So she actually puts a lot of work into these performances," Cannon told E! Online. "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." 

But Twitter users weren't buying it.

Uhm... Did I just catch Mariah Carey lip sync 😳 #BETAwards13

— Aaron MDM Hylton (@itsmdm) July 1, 2013

Mariah Carey the best Lip Sync-er in the business…

— Elián González (@iMalRay) July 1, 2013

#MariahBET is a legend but that high register died back in 99... You look good though with those 4 gallons of whole milk!! #GiveMeOne

— Nucktorious (@Chuckoct) July 1, 2013

Is she really going to lip sing this entire performance? #BETAwards2013 #MariahBET

— Kimberly Harris (@Chemberli) July 1, 2013

Mariah Carey = THEE Worst Lip Sync singer EVER

— Olivia Simone. (@Incredibly_Muah) July 1, 2013

All that money Spent on the backdrop for Mariah Carey just for her to Lip sync

— TMZ Tendaji (@IlluminDaji) July 1, 2013

Why does mariah carey lip sync she's probs the only artist that shouldn't need to

— Emma (@emmapenno) July 2, 2013

Carey faced lip-syncing accusations in May after she performed a medley of her greatest hits on "American Idol," but the singer's rep adamantly denied those claims.

"She ABSOLUTELY DID NOT lip-sync. She performed LIVE in front of several thousands of people!!!! (and did it 3 times!!)," Carey's rep told E! Online at the time. "No LIP-SYNCING whatsoever! She did 3 takes and thrilled the crowd with singing little songs in between that were NOT part of her medley."

Here's Carey's "American Idol" medley performance: 





And here's part of her BET performance: 





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