RENZO JETS IN: Even amid New York’s fashion week frenzy, Diesel founder Renzo Rosso found time to make a West Coast cameo over the weekend. Rosso flew in from New York Friday evening to host his daughter Alessia’s 23rd birthday celebration at West Hollywood nightclub Guy’s, where about 90 guests, including Rosso’s son Stefano, reveled late into the evening, sipping Champagne and dancing to loud tunes spun by the club’s DJ. Alessia Rosso — who appeared to thoroughly enjoy the company of the evening’s hard-partying crowd — has lived in Los Angeles for about two years, and is studying film and TV production, an experience that may soon come in handy as her father said he plans to launch a media outlet under the Diesel brand in the future. “I’m glad she’s here, I love California because it’s got a different energy and is so incredible,” Renzo Rosso said. “The most important people are here, and you can meet them in a friendly way not possible in New York City.” Despite the California love, the elder Rosso didn’t linger in the Golden State, jetting back to New York the next evening for Diesel’s Black Gold show and the brand’s Fifth Avenue store opening today.