Lady Gaga was branded 'a childish diva' by Vogue editor-in-chief Anna Wintour, according to the singer''s biographer.
The British-born journalist met Gaga back in May when she performed at Anna's Metropolitan Museum Costume Institute Gala.
"She (Lady GaGa) sort of had a meltdown before she went on and as it was described to me, Anna was really none too pleased with her. Anna wasn't impressed. She thought she was just behaving like a childish diva and not the professional who was about to perform for her peers; these incredibly famous designers and celebrities," the Sun quoted Maureen Callahan, author of much-anticipated biography Poker Face: The Rise and Rise of Lady Gaga, as saying."She sequestered herself in the back room for a good hour. She was late to perform and I also heard that she had been demanding things. She went to Anna at the last minute and was saying, 'I'd like it to be this way.
"And Anna just said no. I don't think she's used to hearing that very often. When you're dealing with two egos like that, it gets interesting," she added.