Paris Hilton, who recently split from shipping heir fiance Paris Latsis has reportedly hooked up with 20-year-old Stavros Niarchos, whose family is worth a staggering USD 7.5billion.

Both Paris and Stavros (who used to date Mary-Kate Olsen) were spotted at Los Angeles nightspot Spider Club. An onlooker said, "They made out all night."

The following night, the smitten couple partied at Element with Paris' sister, Nicky. A source revealed: "Paris tried to get the club to turn the lights down so no one could see her and Stavros make out."

However, the new romance is said to have upset pretty actress Mary-Kate, who friends claim she feels "betrayed" by her pal Paris.

Stavros' wealthy parents also look set to be unhappy with the blossoming relationship, as they reportedly didn't like him dating Mary-Kate because of the public attention it attracted.