The former, of course, might be a nod to the one of the most famous pieces of jewelry in movie history — the fictional heart-shaped blue diamond from 1997’s “Titanic,” worn by the other important Kate in DiCaprio’s life. But, being that the Heart of the Ocean is well, heart-shaped, a second possible inspiration for the look is a piece of jewelry with more direct significance to Beckinsale. In her co-starring role as Ava Gardner in “The Aviator,” Beckinsale declares to Howard Hughes, played by DiCaprio, that she’s “not for sale,” when he woos her a square-cut blue sapphire necklace.

Beckinsale starred alongside DiCaprio in “The Aviator“ as actress Ava Gardner and aerospace engineer Howard Hughes.
Billy Zane and Kate Winslet in “Titanic,” which turned the fictional “Heart of the Ocean” into one of the most recognizable pieces of jewelry in the world.

Whichever fictional gemstone Beckinsale made larger-than-life, the statement piece was surprisingly not a custom look for the event, but straight from The Blonds Fall-Winter 2023 collection, which showed during New York Fashion Week in February.

Inspired by films such as “Valley of the Dolls” and the jewelry worn by stars like Elizabeth Taylor, the collection — by designer Phillipe Blond and creative director David Blond — was an exuberant, campy celebration of Hollywood glamour, bursting with sculptural corsets, velvet gowns and sequined party dresses that included oversized gemstone motifs.

For her night out, Beckinsale paired the ultra-mini with black tights — a near continuation of the pantsless trend, as the runway version of her look was presented slightly shorter as a top — sky-high reflective platform heels and a big black hair bow.

Other attendees to the Beverly Hills fête included Beyoncé and Jay-Z, Salma Hayek, Kim Kardashian, Zoë Kravitz and Channing Tatum, according to Harper’s Bazaar. But no one else seemed to celebrate the occasion with such a chic sartorial easter egg, leaving Beckinsale’s look a dazzling win for the night.