Meet Pierre Casiraghi, 24-year-old Monegasque prince and grandson of Grace Kelly, pictured here with his sister Princess Charlotte. But be aware: he might look a little bit different after a "vicious" nightclub brawl this weekend — involving Paris Hilton's ex Stavros Niarchos and the former owner of Hawaiian Tropic — that landed him in the hospital.

Casiraghi was apparently left with "deep cuts and blood everywhere" — a witness tells the Post that he "looked like he needed plastic surgery" — when he was jumped (possibly after provoking) Adam Hock, the 47-year-old former owner of Hawaiian Tropic, at Double Seven in the Meatpacking District:

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.

Hock apparently threw the first punch, "cold-cocking" Casiraghi before "punching out" Nicharos and "landing blows" on two other members of the Casiraghi entourage, "downtown hipsters Vladimir Restoin Roitfeld, 27, and Diego Marroquin, 33." Hock's been charged with four counts of assault. If nothing else, sounds like the city needs to start cracking down on these dangerous nightclubs populated by wastrel shipping heirs and hooligan royalty:

At one point, witnesses on both sides agree, a friend of Casiraghi grabbed a bottle of Grey Goose vodka from a nearby table and tried to crack it over Hock's head.

[NYP, image via AP]