Jennifer Lopez stepped out at Vogue World: Milano wearing a 74-carat Dolce & Gabbana necklace. GC Images

Jennifer Lopez is back on the floor.

The “Jenny From the Block” singer, 57, danced her way into the Vogue World Milan show on Tuesday night, taking the hand of a male model from her front-row seat and stepping out to the center of the Galleria Vittorio Emanuele II. After a spin, she raised her arm with a flourish.

The moment put her jaw-dropping Dolce & Gabbana necklace in motion, too.

A male model guided the singer out of the audience midway through Tuesday’s program, giving her a twirl. VogueThe 57-year-old singer had been sitting front row in the Galleria Vittorio Emanuele II. VogueLopez wore a Dolce & Gabbana corseted gown, sheer opera-length gloves and glittering diamond jewelry. GC Images

The piece, from the Italian house’s high jewelry, or Alta Gioielleria, collection, is a white gold and diamond design anchored by a 74.459-carat Paraiba tourmaline.

It was previously worn by Princess Diana’s niece Lady Kitty Spencer at last October’s Grand Prix de la Haute Joaillerie, where the model and aristocrat accepted an award on behalf of the brand’s jewelry line.

On Lopez, the massive stone sat above the neckline of a strapless black tulle corset gown, also by Dolce & Gabbana.

She paired the tea-length dress with sheer black opera gloves and pointed slingback pumps, plus diamond and white gold earrings and a matching ring.

The showstopping necklace was previously worn by Princess Diana’s niece Lady Kitty Spencer. Kitty Spencer/InstagramThe white gold and diamond piece centers on a Paraiba tourmaline sourced from Mozambique. Kitty Spencer/InstagramItaly hosted Vogue World for the first time, with the event opening Milan Fashion Week. @Nacer_photo_ / BACKGRID

Lopez was among the famous guests at the fifth Vogue World, which kicked off Milan Fashion Week and celebrated “Italian fashion, craftsmanship, and creativity in the age of technology.”

“Milan has always stood for the perfect balance between craft and creativity,” Anna Wintour, Condé Nast’s chief content officer and Vogue’s global editorial director, said in a statement ahead of the event. “It’s a city that knows how to make the handmade feel modern and the modern feel timeless. Bringing Vogue World here will be our biggest celebration yet of fashion’s human touch.”

The lavish event raised funds for a neighborhood library in the city’s Quarto Oggiaro district and drew stars like Pamela Anderson, Dakota Johnson and Heidi Klum. Lopez’s fellow New Yorkers Cardi B and Alicia Keys also had cameos on the runway.