The 2016 Met Gala in New York drove Demi Lovato to an Alcoholics Anonymous meeting, because the catty fashion party left her feeling low on self-esteem.

The singer dressed up for the annual star-studded fundraiser for the Metropolitan Museum of Art's Costume Institute, but admits she was miserable - and one unnamed celebrity made a terrible night out really awful.

"This one celebrity was a complete b**ch and was miserable to be around," Demi tells Billboard. "It was very cliquey. I remember being so uncomfortable that I wanted to drink."

Lovato, who has been sober ever since a meltdown on a Jonas Brothers tour in 2010 sent her to rehab for months, texted her manager and went straight from the red carpet to a late-night AA meeting.

"I changed my clothes, but I still had my diamonds on - millions of dollars of diamonds on in an AA meeting - and I related more to the homeless people in that meeting, who struggled with the same struggles that I deal with, than the people at the Met Gala (who were) fake and sucking the fashion industry’s d**k," she recalls.

Demi isn't the only star who has slagged off the Met Gala in recent years - Gwyneth Paltrow vowed to avoid the event forever in 2013, before returning last year.

Days after the bash five years ago, the Oscar winner told USA Today, "I’m never going again. It was so un-fun. It was boiling. It was too crowded. I did not enjoy it at all."

She also told Australian radio hosts Kyle and Jackie O the 2013 Met Gala "sucked".

"It seems like it’s the best thing in the world. You always think, 'Oh my God, it’s gonna be so glamorous and amazing and you’re going to see all these people', and then you get there and it's so hot and it’s so crowded and everyone’s pushing you."