Sophie, 57, twinkled in an aquamarine tiara on Tuesday night for the Buckingham Palace state banquet held during the first state visit of King Charles III’s reign. The diplomatic dinner honored Cyril Ramaphosa, President of South Africa, during his visit to the U.K.

Sophie sported a regal headpiece to match the formality of the occasion. The Countess of Wessex was elegant in an emerald evening gown and her eye-catching sparkler, which features a large aquamarine center stone flanked by wave-like arrays of diamonds. The Court Jeweller reports that the tiara was made especially for Sophie, who first debuted it at the enthronement festivities for Prince Albert II of Monaco in 2005.
In a unique twist, the piece is convertible, and can alternatively be worn as a necklace. Sophie styled it this way for a London gala in 2006, with the diamond waves cascading down.
The royal seems to reach for blue-hued jewels, borrowing Queen Elizabeth’s aquamarine ribbon tiara to wear for the wedding of Princess Madeleine of Sweden and Christopher O’Neill in 2013.
She further accessorized Tuesday with two pieces that belonged to her late mother-in-law: earrings from the Pear-Shaped Diamond Demi-Parure and the Modern Fringe Necklace, according to the Court Jeweller. Sophie and the Queen were famously close, and the jewelry was a thoughtful homage to their tight bond.
Sophie attended the state dinner with her husband Prince Edward, who was tasked with an important duty the following day. On Wednesday morning, the Earl of Wessex, 58, accompanied President Ramaphosa to two environmental engagements, touring the Royal Botanic Gardens, Kew and the Francis Crick Institute, highlighting scientific initiatives between South Africa and the U.K.
Prince Edward’s solo outing with the world leader is a signal of the elevated royal role he might play during his brother’s reign. Last week, Charles, 74, asked British Parliament to make Prince Edward and Princess Anne Counsellors of State.
On Dec. 1, the Earl and Countess of Wessex will attend the annual Royal Variety Performance as the evening’s guests of honor. It will mark the first time that the couple attends the show, which has previously been attended by the King, Prince William, Princess Kate, Prince Harry and Meghan Markle.