Christina Aguilera racked up a massive $4000.00 bar bill while partying in London last night . The 'Beautiful' singer was enjoying an evening out at London's trendy Kabarets Prophecy club and wasted no time in getting into the party spirit. However, Christina, 25, was later seen being carried out of the venue by her minders after apparently having one too many glasses of champagne. Her unsteady exit was later blamed on exhaustion, rather than excessive drinking. A source told Britain's Daily Mirror newspaper: "Not only is she very little but she was quite tired because she's in the middle of her tour. She only sipped a few glasses of Veuve Clicquot champagne and one vodka shot. Her party still ran up a pretty sizable bar bill, mind you. "Christina, who is married to music executive Jordan Bratman, looked stunning in a white fitted jacket and jeans as she joined a host of other stars, including The Black Eyed Peas, for the private bash.