The Princess of Wales wore the Queen Mary's Lover's Knot Tiara with a lemon-yellow Elie Saab cape gown at the state banquet for Sultan Haitham bin Tariq al Said at Windsor Castle on Tuesday evening.
The banquet marked the first day of the Sultan of Oman's three-day state visit, the first by an Omani monarch to the United Kingdom in more than 40 years, according to Harper's Bazaar.
Kate's dress came from Elie Saab's Spring/Summer 2025 ready-to-wear collection. The pleated design features a woven crew neck, empire waist, semi-sheer skirt with a matching bodysuit underneath, and a diaphanous cape trailing behind, Harper's Bazaar reported.
She paired the gown with the Lover's Knot tiara, which she first wore in 2015. The piece was made by Garrard for Queen Mary in 1913 and features diamond arches with 19 pearl drops. It was later passed to Queen Elizabeth II, who lent it to Diana, Princess of Wales, on several occasions. Diana last wore it in 1991, Page Six reported.
Additional jewelry included the Greville chandelier earrings and Queen Mary's diamond choker bracelet, both from the late Queen Elizabeth II's collection, Page Six noted. She also carried a gold glitter Anya Hindmarch clutch and wore Aquazzura gold sequined pumps.
Earlier in the day, the Princess of Wales welcomed the sultan at a formal ceremony in a bespoke emerald-green Alexander McQueen coat over a black lace turtleneck, with a matching Juliette Botterill fascinator.
She pinned the Queen Alexandra Three Feathers Brooch, set with diamonds, rubies and emeralds in gold originally mined in Merionethshire, North Wales. The brooch was crafted by Garrard in 1863 and presented to Queen Alexandra as a wedding gift by the Ladies of North Wales, Page Six reported. It bears the motto "Ich dien" (I serve). Green is one of Oman's national colors.
Prince William wore a Windsor tailcoat with the Order of the Garter and a sash bearing the Lesser George, Page Six said.
The Princess of Wales also wore the Royal Victorian Order sash, star and badge, and the King Charles III Royal Family Order ribbon, as is customary for state banquets.
ELLE reported that the Lover's Knot tiara has become a staple for the Princess at state banquets, most recently worn for the Nigerian state visit in March.