Say it ain't so, Petra Nemcova! The tsunami-surviving supermodel, who just broke up with fey singer James Blunt, rebounded with Paris Hilton's ex, Stavros Niarchos. Our eagle-eyed spy caught the two making out at Bungalow 8 recently as they partied with Niarchos' oil-heir friend Brandon Davis. "She was grinding him," our witness said. "It was pretty gross. I mean, he used to sleep with Paris. Eww." A rep for Nemcova said, "I haven't heard of this."