The O.C. beauty Mischa Barton is rumored to be dating rugby star Mark Robinson after the pair were caught kissing at a London hotspot last week. The 20-year-old British-born actress had been dating rocker Cisco Adler but reportedly hooked up with the 30-year-old sportsman at a swanky bash in Windsor, England.

An onlooker at the party tells British newspaper the News Of The World, "Mark couldn't believe his luck. One minute they were standing there talking and the next they were all over each other in the corner of the tent. They were snogging (kissing) and running their hands over each other's bodies. They didn't seem to care who saw."

A close friend of Robinson adds, "He's been smiling all week and has told pals but won't talk publicly."

-See photos of Mischa.

(This news article provided by World Entertainment News Network)