Thoughts of Old Hollywood may conjure visions of bombshell glamour, decadence (if not full-on debauchery), glittering diamonds…and Chanel. The French fashion house has a long history with Tinseltown, dating back to the 1930s, when United Artists mogul Sam Goldwyn invited Mademoiselle Gabrielle “Coco” Chanel from Paris to design gowns for his Los Angeles starlets, on and off-the-screen. In Babylon, Damien Chazelle’s bombastic (not-so-)Golden Age of Hollywood epic, the collaboration continues.

Early in the film, fearless ingénue Nellie LaRoy (Margot Robbie) assuredly marches up to the box office for the premiere of her 1926 silent film debut. The staffer refuses to let the still-unknown talent in, but the resourceful Jersey girl bribes her way into the theater regardless. The camera closes in on Nellie’s apprehensive-turned-elated expressions as she awaits the audience’s reaction to her performance. Her face and long, undone curls—an unexpected style for the decade, but based on real-life Hungarian starlet Lya De Putti—are framed by a pair of brilliant deco-style earrings, appropriately christened “Muse,” from the Chanel High Jewelry collection.

Through a partnership with the luxury house, costume designer Mary Zophres carefully selected the white gold earrings—radiant with 26 carats of sapphires and 5 carats of diamonds—to perfectly accent Nellie’s sparkling milestone event ensemble: a blue hand-beaded halter top and tap pants set.

“Now she has some money and she’s gonna spend a little bit more,” says Zophres, who received one of her three Oscar nominations for Chazelle’s 2017 hit La La Land. “She wants something that’s glittery because she’s still Nellie.”

The actress’s premiere earrings, with triangular diamonds and sapphires arranged into star shapes, feels felicitous, and even literal, for her ascendance. They also serve as a cautionary tale for neophyte talent thrust into the spotlight with unprecedented paychecks. “I think she blows her whole wad on a pair of diamonds because she hasn’t had money her whole life. She may not have spent it wisely, but she wanted something for herself,” says Zophres, emphasizing the storytelling behind Nellie’s splurge.

The glittering look is a reference to, but also a departure from, the scarlet red and skin-baring outfit Nellie wore when she was plucked out of a bacchanalian dance party for her big break. Inspired by a ’20s image of Asian American actress Anna May Wong, Zophres imagined Nellie was previously a dancer in New York City and configured a red silk scarf with a pair of color-coordinated tap pants that she possibly pilfered from a studio back in the day. She’s come a long way since then.

At the height of her silent film stardom, Nellie is mobbed by fans and paparazzi in rainy New York City. Coincidentally, kindred spirit Manny (Diego Calva), former producer’s underling-turned-studio exec, spots Nellie and shields her from the scrum into her chauffeured car.

He’s in the city to witness the public reaction to Al Jolson’s game-changing sound musical, The Jazz Singer—a harbinger of the end of silent films. An unusually understated Nellie is there to visit her mother, a longtime patient in a mental institution. In a pristine vintage celadon green cloche hat and matching shawl lapel wrap coat, Nellie is practically dressed for the harsh East Coast climate—and the emotionally intense meeting. “That costume was actually a cocoon for her,” says Zophres. “It’s the only time she wears a hat, and she never really takes that coat off. It’s her way to hug herself.”

The costume designer also spotted an opportunity to incorporate an 18K white gold Chanel tasseled lariat, glimmering with 17 carats of paved stones and close-set diamonds. “She couldn’t help herself,” says Zophres, imagining Nellie’s mindset in adorning herself with the elegant, yet opulent accessory. “‘I don’t really want to dress in a [flashy Hollywood] way, but I’m gonna wear my diamonds.’”

Fittingly, the necklace, stunning with intricate lacework that culminates in a camelia burst, is named for actress Lucienne Roger, who starred in the 1910 Belgian satirical comedy play, Le Mariage de Mademoiselle Beulemans (The Marriage of Mademoiselle Beulemans). “It was a beautiful piece that felt 1920s to me,” says Zophres.

The usually brash Nellie maintains sartorial decorum and sensitivity, though. Before she enters the hospital, she quietly removes and relinquishes the necklace to her driver to hold. After seeing her mother, Nellie remains stripped of the jewels, as she and Manny reveal their own, long-buried family traumas to each other. She then redons the luxurious ornament—and her star persona—as she quickly bids Manny adieu with a wide grin and runs off into the night. “It was one of those things that is carefully placed for very specific reasons that have to do with character development,” says Zophres.

The costume designer also refers to Nellie’s refined, yet dramatic—and diamond-accessorized—ensemble as one of her “Gloria Swanson moments,” which also feels like a reality-meets-fiction crossover. During her time at United Artists, Mademoiselle Chanel did, in fact, design gowns for Swanson, notably to play an opera diva in 1931’s Tonight or Never. The real-life screen icon was making her transition from silent to sound films, just like Nellie’s impending path in Babylon.