Mariah Carey has been accused of lip syncing during her highly-anticipated American Music Awards performance on Tuesday night (09Oct18).

The 48-year-old singer donned a stunning pink dress to perform the world TV debut of her new track With You on stage at the Microsoft Theater in Los Angeles, California. And while many fans praised Mariah for her flawless performance, others suggested the mother-of-two had actually pre-recorded the vocals, and was lip syncing.

"Stop lipsyncing Mariah,” one user wrote, while another tweeted: "Mariah looks great but why is she lip syncing?!" A third wrote on Twitter: "Someone take Mariah to karaoke and teach her how to lipsync better #AMAs."

When contacted about the lip syncing claims, a representative for Mariah said: "Wow we can’t even get through five minutes without someone trying to tear her down."

Mariah hasn't had much success with lip syncing in recent years. She hit headlines worldwide after her performance of Emotions on Dick Clark's New Year's Rockin' Eve with Ryan Seacrest in 2016, when her in-ear audio stopped working and drew attention to the fact she wasn't singing live.

Following the embarrassing situation, Mariah admitted she was "mortified" by what had happened.

"It’s not going to stop me from doing a live event in the future," she added to Entertainment Weekly magazine. "But it will make me less trusting of using anyone outside of my own team."

Mariah's AMAs performance was the first time she has performed at the star-studded ceremony since 2008. With You is the first single to be taken from her forthcoming as-yet-untitled album.