Calvin Klein uncomfortably came face to face with his ex-wife Kelly Klein at a fancy dinner in the Hamptons on Sunday night. The former couple, who divorced after two decades together in 2006, were both guests at fashion photographer Bruce Weber’s surprise party for his wife, Nan Bush, at Nick Hatsatouris and Lincoln Pilcher’s summer restaurant Moby Dick’s in Montauk. A spy told us, “Everybody was watching to see how they would interface, but they just ignored each other.” Guests at the dinner included Grace Coddington, Cornelia Guest, Ingrid Sischy, Helmut Lang, Sandy Gallin, Nacho Figueras and his wife, Delfina Blaquier.