Mariah Carey "absolutely did not lip-sync" during her American Idol finale performance.

The international songstress took to the stage during Thursday's final to perform a medley of her greatest hits.

A number of people weighed in on the star's performance, claiming her vocals weren't live.

However, Carey's representative has now slammed the rumours, announcing in a statement: "She ABSOLUTELY DID NOT lip-sync. She performed LIVE in front of several thousands of people!!!! (and did it 3 times!!).

"No LIP-SYNCING whatsoever! She did 3 takes and thrilled the crowd with singing little songs in between that we're NOT part of her medley."

Carey's representative confirmed that she did sing to a pre-recorded track which is common practice in the industry.

Meanwhile, a host of people took to Twitter to slam the star's performance.

On user tweeted: "Mariah Carey….worst lip syncer ever! @americanidol ha," while another wrote: "How is Mariah Carey going to lip-synch on a show about singing live? That's like the host of Intervention doing heroin during the show (sic)."