SAN MARINO, Calif. — Bronx-born Ralph Lauren, a quintessential New Yorker, had never staged a runway show on the West Coast before. So clearly, with his first show in sunny California, he was going to go big — or, well, stay home.

Big he went, staging a sumptuous display of his well-honed ethos of casual luxury, with strong Western accents like cowboy hats and boots, against a setting sun at the grand Huntington Library, Art Museum, and Botanical Gardens in San Marino, California, near Los Angeles.

Rivaling his lavish 50th anniversary show in New York’s Central Park in 2018, Thursday’s extravaganza brought in a slew of movie stars — including newlyweds Jennifer Lopez and Ben Affleck — to watch more than 120 models strut the runway, including some adorable tots in Lauren’s childrenswear who had the fashionable crowd gasping with delight.

“We’re in show business,” the 83-year-old designer said simply in a post-show interview, standing next to the endlessly long, candlelit tables where guests dined post-show on Polo Bar burgers, grilled branzino and other specialties from his restaurant in New York.

Lauren explained that early on, he had felt LA wasn’t his style, but that changed and he finally decided, “OK let’s do something in LA, but let’s do it great.”

Always a celebrity magnet, Lauren brought out a slice of A-list Hollywood with Lopez and Affleck, Ashton Kutcher and Mila Kunis, Sylvester Stallone, John Legend, Diane Keaton, Jessica Chastain, Laura Dern, Chris Pine and James Marsden, to name a few.

The intimate affair for some 200 people began with cocktails and hors d’oeuvres like tuna tartare on a patio overlooking the lush lawns and gardens of the Huntington, which once housed Gilded Age tycoon Henry Huntington. Celebrity guests mingled along with TikTok influencers and Lauren customers.

As the sun sank lower, guests were summoned to the tiled entrance of the museum, where models strutted to a soundtrack of California-themed songs like “California Dreamin.”

There were plenty of cowboy hats, worn-in jeans and boots to begin with, gradually morphing into fancier wear like long, bright skirts and slinky cut-out gowns for the women.

A gasp traveled through the crowd as two small children appeared, each holding one hand of their accompanying adult, dressed in classic Lauren looks of tweed jackets, sweater vests, pinstriped button-downs and white shorts.

More children followed, including a little boy in bright green trousers who stole the moment by insisting on high-fiving everyone he passed.

The show, which featured designs from several Ralph Lauren lines including menswear and childrenswear, finished with the models all returning to gather on the patio, joined by Lauren as he emerged to cheers.

Over dinner, Kushton and Kunis chatted with Legend, who said in an interview before the show that Lauren is “obviously an icon in the fashion business and has meant so much to style for such a long time.”

Lopez noted that Lauren had dressed her and Affleck for their recent nuptials. “Ralph did our wedding, so we’ve become quite close,” the pop star said. “And we really love his aesthetic.”

And singer Maggie Rogers noted she had grown up as a fan of the brand. “I have been watching them for the last couple of years and to me they represent such a timeless American style, and I always try and bring that … classic thing to my music,” she said. “So it feels like the perfect match.”

The show’s soundtrack ended with a song that seemed to acknowledge Lauren’s divided feelings, geographically speaking. “Well I’m New York City born and raised,” went the Neil Diamond song “I Am … I Said,” “but nowadays I’m lost between two shores. L.A.’s fine, but it ain’t home. New York’s home but it ain’t mine no more.”