The Princess of Wales stepped out on Tuesday for an important state visit alongside Prince William and the King and Queen. For the occasion, the Princess chose a historic brooch once owned by the late Princess Diana, and matched her ensemble to the green of the jewellery’s impressive stone.

Tuesday (20 October) marked an official state visit by the Sultan of Oman, with an official carriage procession bringing the Royal Family and their guests to Windsor Castle, including a Guard of Honour. The royals were photographed as they lined up waiting to greet Sultan of Oman Haitham bin Tarik and other guests, appearing to be in high spirits as they chatted together. After the formal greeting, the group split into their carriages, with The Prince and Princess of Wales travelling in the Australian State Coach alongside Oman’s Deputy Prime Minister for Economic Affairs and its Secretary General.

windsor, united kingdom october 20: haitham bin tarik, sultan of oman is greeted by king charles iii (l) and queen camilla (c) at the start of a three day state visit in windsor, united kingdom on october 20, 2026. prince william and princess catherine (r) of wales also attended the greeting. (photo by ray tang/anadolu via getty images)
Anadolu
windsor, united kingdom october 20: haitham bin tarik, sultan of oman is greeted by king charles iii and queen camilla at the start of a three day state visit in windsor, united kingdom on october 20, 2026. prince william (l) and princess catherine (r) of wales also attended the greeting. (photo by ray tang/anadolu via getty images)
Anadolu
windsor, england october 20: catherine, princess of wales and prince william, prince of wales at the formal welcome on the royal dais, during the state visit of the sultan of oman to the uk on october 20, 2026 in windsor, england. sultan haitham bin tarik, sultan of oman, is on a three day state visit to the uk. (photo by mark cuthbert/getty images)
Mark Cuthbert

Both Queen Camilla and the Princess of Wales opted for monochrome midi coat looks, with the Queen in red and Kate in a deep shade of emerald-teal. The Princess’s autumnal coat was a fitting choice, given the brooch she chose for the occasion, which features a large, detachable pendant of cabochon emerald. The symbol within the diamond and emerald body of the brooch represents the Prince of Wales, making it a fitting choice, considering her and Prince William’s titles.

windsor, england october 20: catherine, princess of wales at the formal welcome on the royal dais, during the state visit of the sultan of oman to the uk on october 20, 2026 in windsor, england. sultan haitham bin tarik, sultan of oman, is on a three day state visit to the uk. (photo by mark cuthbert/getty images)
Mark Cuthbert

The Prince of Wales Feathers Brooch has a long history, spanning back to the 1800s, when it was a wedding gift for Princess Alexandra of Denmark’s marriage to King Edward VII (who was then Prince of Wales), according to Royal Watcher. It was later passed to the Queen Mother, who gifted it to Princess Diana to celebrate her engagement to King Charles. Princess Diana often wore the brooch as a necklace pendant, with or without the emerald droplet.

hobart, australia march 30: diana, princess of wales, wearing a red dress designed by bruce oldfield, the spencer tiara and the royal family order of the queen and the prince of wales feathers diamond necklace, smiles as she attends a reception at the wrest point hotel on march 30, 1983 in tasmania, australia. (photo by anwar hussein/getty images)
Anwar Hussein
Princess Diana wearing the brooch in pendant form in Australia in 1983.

This week, the Princess of Wales chose to wear the full brooch attached to her stylish autumn coat, and added a co-ordinating hat for the formal occasion.

windsor, england october 20: catherine, princess of wales, attends a welcome ceremony at datchet road during the state visit of the sultan of oman to the uk on october 20, 2026 in windsor, england. sultan haitham bin tarik, sultan of oman, is on a three day state visit to the uk. (photo by andrew matthews wpa pool/getty images)
WPA Pool

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The three-day Oman state visit continues.