The backstage crisis behind Selena Gomez's 'horrible' AMA's performance

Selena Gomez was hit with criticism after her 'horrible' performance, but there was a sad reason behind her shaky vocals at the American Music Awards.

A source close to the singer says Selena suffered a panic attack before she took the stage at the American Music Awards.

"Selena definitely had an anxiety and panic attack before she went out and was putting a lot of pressure on herself," the source told E! News.

Viewers called her performance of her latest single Lose You To Love Me "horrible" and "embarrassing".

Selena Gomez performed Lose You To Love Me at the American Music Awards. Photo / AP

"That was god awful," wrote a viewer on Twitter.

"I love you Selena but that wasn't good at all, you can do better," a fan posted.

.@selenagomez's POWERFUL PERFORMANCE, a story in two parts: #AMAs pic.twitter.com/I0hx01eNP8

— MTV (@MTV) November 25, 2019

That was god awful

— Barbara Vyse (@Bvyse19) November 25, 2019

Lose You To Love Me is rumoured to be about her ex-boyfriend Justin Bieber.

The performance was tipped as the 27-year-old's big comeback and was her first TV performance in two years.

Dressed in a floor-length black long-sleeved gown, Gomez belted out the song, which includes the lyrics: "You promised me the world and I fell for it. I put you first and you adored it. Set fires in my forest, and you let it burn. Sang off-key in my chorus. 'Cause it wasn't yours."

Gomez was supported by her musician friends Taylor Swift and Halsey at the ceremony.