What happens when you mix Valentino, Sofia Coppola and the Teatro dell’Opera di Roma? “La Traviata,” an opera that previewed Sunday night to an audience that included Kim Kardashian and Kanye West, Elizabeth Hurley, Keira Knightley, Vanessa Beecroft and Diane von Furstenberg. It’s director Coppola’s first foray into the world of opera, and she brought along her film world friend Nathan Crowley (“Batman Begins” and “The Dark Knight”) to make the sets. Maison Valentino creative directors Maria Grazia Chiuri and Pierpaolo Piccoli designed costumes for the cast, save for four gowns worn by soprano Francesca Dotto, who plays the lead character, Violetta – those were created by Mr. Valentino Garavani himself. And in case you were wondering about the power of bringing these contrasting worlds together: the 15-performance run is already nearly sold out.