Lady GaGa had to be dragged out of her dressing room by Oprah Winfrey after suffering from stage fright.

The 'Telephone' singer hid backstage prior to her performance at the Costume Institute Gala at the Metropolitan Museum of Art on Monday (03.05.10) - which was attended by an exclusive crowd of 700, including Anne Hathaway, Taylor Swift and Jennifer Lopez - but the talk show host helped her overcome her nerves.

A source told the New York Post newspaper: "She literally wouldn't come out. Friends tried, Warner Music executive Lyor Cohen tried, no dice. Eventually, Vito Schnabel came over and got artist Terence Koh on the phone to talk to her, which helped. Koh and Oprah were the ones who finally coaxed her out."

However, the eccentric performer was told she could only perform at US Vogue editor Anna Wintour's annual fete on the premise she was polite and didn't swear on stage.

She quipped to the crowd in New York City: "I'll never forget when Anna Wintour called me to play at this event, she called me and said, 'I would like you to play at the Met gala, but I just want to make sure, because I've seen you perform before, that you won't be swearing during the performance.' So Anna, I will do my f**king best!"

The 'Just Dance' hitmaker's performance seemingly got the guests in the mood for a singsong, as a number of A-list stars belted out tracks at the exclusive after party at the Mark Hotel.

A source added: "Pharrell Williams first jumped in and started singing 'Beautiful,' and then Sean Combs jumped up and started rapping to 'All About the Benjamins.' He even grabbed Anna Wintour into the deejay booth. Finally, Usher and Justin Timberlake joined in."