Mischa Britney Barton

30-11-2006 20:00

Mischa Barton gave an impromptu performance of Britney Spears' hit song 'Oops!... I Did It Again' during a night out partying.The former 'O.C.' actress was enjoying an evening out in London on Tuesday (28.11.06) when she decided to treat revellers at the trendy Paper nightclub to some of her singing.Mischa, 20, jumped on stage and launched into the famous track, and even treated clubbers to a sexy dance routine. One onlooker said: "She got on stage clutching a microphone and a bottle of champagne. She seemed a bit drunk, but her singing was good. She certainly can hold a note."Mischa isn't the only young star who has been enjoying London's nightlife this week.Christina Aguilera racked up a massive £2,000 bar bill while partying in the UK capital on Tuesday (28.11.06).The 'Beautiful' singer wasted no time getting into the party spirit at Kabarets Prophecy club, and she was later seen being carried out of the venue by her bodyguards after apparently having too much champagne.