Mariah Carey’s performance at the “American Idol” finale might have captivated the live audience, but not those who watched from their TV sets. The multiple Grammy winner has been hit by lip-syncing accusations on Twitter.

When the diva took the Idol stage on Thursday and sang a medley of her greatest hits, people watching at home quickly questioned her performance. Many of them believe that she did not sing live in the show.

“Watching Mariah Carey lip sync is the most painful thing in the entire world,” according to a Twitter commenter named lauren mahaffy.

Another commenter named King Tml wrote: “@MariahCarey Great job ‘live’ singing on American idol finale!! I can lipsync better than you!!AMATEUR :p”

“She was singing along to pre-recorded tracks, but it was clear at times she wasn’t singing the real high notes. The audience was embarrassed for her,” a source told examiner.com.

However, a rep for the chart-topping music superstar denied the reports. Although the rep admitted that Mariah sang to a pre-recorded track, which is a common practice in the industry, she still “performed with a 40-person choir” and “SANG LIVE.”

“She ABSOLUTELY DID NOT lip-sync,” the spokesperson told eonline.com. “She performed LIVE in front of several thousands of people!!!! (and did it 3 times!!).”

The rep reiterated, “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.”

But perhaps the discrepancy between Mariah’s lip movement and the audio can be blamed on the FOX talent show’s poor video editing.

An unnamed music producer studied Mariah’s performance, and said that it appears her rep is telling the truth.

“It’s a tough call. At around 2:15 to 2:21 in the clip she appears to be out of sync with the audio. That’s the one spot I think could be the giveaway that she’s lip syncing,” the producer told RadarOnline.com.

“However, sometimes a slight delay in the audio sync to the video can also make someone look like they are lip syncing when they are not. It could just be a bad edit.”

Apparently, this isn’t the first time Mariah has been caught “lip-syncing.” Several compilation videos on YouTube claim that she has done it numerous times before.

Lip syncing or just bad sound editing? Watch Mariah’s performance here:

One of the several compilation videos on YouTube that claim Mariah Carey lip syncs in her live performances: