AceShowbiz -

Mischa Barton has suffered a wardrobe malfunction Wednesday night, September 17, flashing a breast while leaving a fashion show in London. The actress' breast apparently slipped off her dress while she was hopping into a taxi.

Always one to take chances with her wardrobe, Mischa attended the Fashion For Relief fundraiser, held at the BFC tent at the Natural History Museum in downtown London. During the event she was seen wearing a red-and-gold satin evening gown. She even beautified her look by wearing silver bangle bracelets and leather heels.

She was about to leave the hot spot when she was seen jumping into a taxi. Unfortunately for her that her dress suddenly lowered down her shoulder, exposing her left breast. Quickly straightening her dress, she was then photographed covering her face with both of her hands.

In between her public appearances, Mischa has been the target of media speculation lately. She was rumored to be dating actor Josh Hartnett after being spotted with him at trendy club Bungalow 8 earlier this week. Denying report of a romance, she was accused to have an affair with her close friend Nicole Richie's partner and baby's daddy Joel Madden.

Star magazine which broke the affair rumor claimed its spies witnessed the actress dancing wildly in front of Joel as he jammed with his rock band Good Charlotte at Hollywood's posh Chateau Marmont on September 7. Nicole, who was enjoying runway shows during New York Fashion Week, was furious after being informed by her best friend Paris Hilton that Joel and Mischa enjoyed dirty dancing. Feeling betrayed, the celebrity socialite reportedly has moved out of the house they've been sharing. Mischa, however, has not yet commented on the affair report.

Pictures of Mischa's nip slip moment can be seen on Mail Online.