Princess Kate attended her first film premiere in four years on September 22, joining Prince William, Tom Cruise and David Beckham at the premiere of Cruise’s latest movie, Digger. She leaned into fall 2026’s hottest color trend on the red carpet, wearing a new purple gown by Jenny Packham, but it was her Heart of the Ocean-esque necklace that truly stole the show.
The Princess of Wales pulled a major surprise out of the royal jewelry vaults, wearing the Queen Mother's Amethyst Sautoir Necklace—a rare piece that has only been seen in public once since 1925—paired with Princess Diana's Collingwood Pearl Drop Earrings.
"Catherine has never been afraid of color on the red carpet,” Nilesh Rakholia, jewelry expert and founder of Abelini, tells Marie Claire, adding what makes the Digger premiere “genuinely different is the necklace itself.”
The Queen Mother received the long strand of pearls accented with amethysts as a wedding gift from Queen Alexandra in 1923. The bold design is a sautoir style that was popular in the 1920s, and the name comes from the French phrase porter en sautoir, which means to wear something draped over the shoulder or down the back.
The Queen Mother was never photographed wearing the necklace, although she was recorded as having worn it in 1925 during the mourning period following Queen Alexandra’s death, per The Court Jeweller.
“This is a piece that's been worn in public only twice in over a hundred years, and tonight was the first time she's ever worn it,” Rakholia says of the Princess of Wales. “That takes a very different kind of confidence to simply choosing a strong color." The jewelry pro adds that what “strikes” him about the amethyst design “is the rarity of it.”
Queen Camilla is the only person to have publicly worn the necklace before Kate, and ironically, she also chose it for a movie moment, wearing the sautoir to the 2012 premiere of Skyfall with a rich purple gown.
“Reaching for something that infrequently seen, rather than a piece from her more familiar rotation, tells you this was designed to make an impact specifically through the jewelry,” Rakholia shares.
He adds that the sautoir style is part of why the look reads as so current despite the necklace's age. "Sautoir necklaces have that long, dropping silhouette, which is why this piece still looks modern nearly a century on,” Rakholia says. “The elongated drop is very close to what we'd now consider a statement necklace, which is a clever way to wear historic jewelry without it looking like a costume piece."
The Princess of Wales added another heirloom piece of royal jewelry to her outfit in the form of Princess Diana’s beloved pearl drop earrings—a piece that Kate frequently chooses for formal occasions.
"Layering in Diana's pearls alongside a piece with this much history behind it made for a genuinely considered look,” Rakholia says. “It was a deliberate pull from the vault, and that's what made it stand out on a red carpet full of A-listers."