Monaco’s Prince Pierre Casiraghi was beaten for Russian supermodels.

A vicious fight involving vodka and supermodels at a Meatpacking District nightclub sparked a royal beatdown that landed Monaco’s Prince Pierre Casiraghi in the hospital, The Post has learned. The attack on the 24-year-old son of Princess Caroline and grandson of Grace Kelly came during a late-night confrontation between the prince and his playboy pals and former Manhattan club owner Adam Hock at trendy Double Seven on Saturday, witnesses and law-enforcement sources said. After the fight, “Pierre’s face looked broken, with deep cuts and blood everywhere,” said one stunned witness. “He looked like he needed plastic surgery.” Hock, 47, had been partying with friends — including Double Seven owner Jeffrey Jah, hairdresser-to-the-stars Joel Warren and catwalk stunners Natasha Poly, Valentina Zalyaeva and Anja Rubik — when Casiraghi strolled over to their table with shipping-scion pal and Paris Hilton ex Stavros Niarchos III and two other men at around 2:30 a.m., witnesses said. Members of Hock’s group said the prince and his entourage “were being completely obnoxious,’’ insulting the models and swigging from a $500 bottle of vodka on Hock’s table. “The next thing I saw, all hell broke loose,’’ one witness said. Hock allegedly cold-cocked Casiraghi, sending him sprawling. Casiraghi “fell very badly. He . . . flew across the room and landed on a table on the other side,” the onlooker said.