Mischa Barton has been living a jet-set life, after taking a holiday in Hong Kong, which followed a city break in London.
The OC star was seen partying in London's trendy Paper nightclub, with eyewitnesses saying she seemed a little worse for wear.
Perhaps it was the levels of alcohol which she had consumed that persuaded Mischa to jump up on stage, clutching a microphone and a bottle of champagne, and begin singing.
The 20-year-old apparently belted out Britney Spears' Oops
I Did It Again in front of delighted revellers, many of whom said the actress had a good voice.
Following all the partying, Mischa left London and headed for Hong Kong where she attended the opening of a new Chloe store.
The star, who plays Marissa in the OC, displayed her love of fashion by appearing in two different outfits during the launch party.
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