The King and Queen hosted the diplomatic reception on Tuesday evening with Camilla sporting the emerald tiara worn by Princess Eugenie on her wedding day.
The Prince of Wales made a solo appearance as the Princess of Wales missed the annual white-tie and tiara event for the second year in a row. The royals mingled with over 900 diplomats in the state rooms at Windsor Castle for the first time since 2001. Traditionally, the event takes place at Buckingham Palace.
It comes after Kate issued a rallying call to business leaders to prioritise "time and tenderness just as much as productivity and success" as she delivered a speech at a summit aimed at driving further action and investment in the early years development of children, earlier on Tuesday.
The Princess missed the reception for the first time in a decade last year amid her recovery from cancer. While royal fans missed out on another spectacular tiara moment from Kate on this occasion, she is expected to join the senior royals at the German state banquet at Windsor Castle next month.
Kate, 43, wowed at the French state banquet in July in a ruby red Givenchy gown with the Lover's Knot tiara. Just two months later, at the fete for US President Donald Trump, the royal chose a gold lace Philippa Lepley number and once again, the Lover's Knot tiara, which was once synonymous with her late mother-in-law, Diana, Princess of Wales.
See the best photos from this year's diplomatic reception…
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© Alamy Live News.The King and Queen welcomed guests to Windsor
The King and Queen made quite the entrance at the reception, with Charles donning a traditional Windsor Coat with its distinctive red collar and cuffs, and Camilla in a floor-length white embroidered gown.
The garment is only worn at the Berkshire castle, and the custom dates back to the reign of King George III, who adopted the idea from Frederick the Great, who used to dress his staff in a combination of a navy coat with red embellishments.
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© Alamy Live News.Camilla also wore diamond drop earrings
Queen Camilla brought back the Greville Emerald Kokoshnik Tiara, which features diamonds on the band with a large central emerald. The Art Deco-style headpiece was made by Boucheron in 1919 for Dame Margaret Greville, whose jewels were later inherited by the Queen Mother and passed down to Queen Elizabeth II. It had remained unseen until 2018 when Princess Eugenie wore it on her wedding day to Jack Brooksbank.
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© POOL/AFP via Getty ImagesCamilla wore some beautiful jewels
The Queen sparkled in the earrings from her pear-shaped demi parure and her diamond Van Cleef & Arpels serpent necklace.
Her Majesty also sported her Garter star and sash and King Charles's Royal Family Order.
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© GettyA look back at the tiara's last appearance
Princess Eugenie wearing the emerald and diamond headpiece on her wedding day in October 2018.
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© Alamy Live News.Their Majesties greeting guests
The reception, held by the sovereign, celebrates the presence in London of one of the largest Diplomatic Corps in the world and allows Their Majesties to meet representatives of countries accredited to the Court of St. James.
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© Alamy Live News.A bird's eye view of proceedings
The royals mingled with guests in St George's Hall at Windsor Castle.
The evening usually includes a buffet supper and dancing.
Foreign ambassadors and high commissioners based in the UK, their spouses or partners, and diplomatic staff were among those who were entertained.
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© Alamy Live News.The Prince of Wales chatting with guests
The Prince of Wales made a solo appearance at the reception for a second year in a row.
Like his father, Prince William also wore the Windsor Coat, but with classic trousers, instead of traditional knee breeches and buckled shoes.
