The Princess Royal, 73, was seen wearing the Sue Palmer white bolero jacket and Maureen Baker evening dress she wore for her 70th birthday portrait.
The special dress had intricate lace detailing and was a floor-length piece. The King's sister also wore a blue sash and a pair of full-length white gloves. She was also seen holding onto a white clutch with bead details.
The white bolero was adorned with a special touch, the Ribbon Brooch that her brother the King bought her as a wedding present in 1973, and she wore the matching Festoon necklace and Diamond Festoon tiara.
According to The Royal Watcher, the Diamond Festoon tiara was given to the Princess by the World-Wide Shipping Group, a firm based in Hong Kong after she christened one of their ships. Since then she has worn the incredible sparkling tiara on many occasions. Most notably, she stunned in the piece at an Indonesian state banquet in 2012 and even allowed her ex-daughter-in-law Autumn Phillips to wear it when she married the Princess' son in 2008.
The Ribbon Brooch was equally impressive and came with diamond-set tassels and a central diamond cluster. Anne wore her hair in her signature updo and wore minimal makeup for her usual natural look.
The late Queen's daughter was in good company at the state banquet last night when it comes to dressing to impress. The Princess of Wales, 41, looked utterly spellbinding as she debuted the Strathmore Rose tiara. The tiara has a special history as it was a wedding gift to then Lady Elizabeth Bowes-Lyon (later the Queen Mother) from her father, the Earl of Strathmore and Kinghorne in 1923.
The tiara accessorised a beautiful white Jenny Packham gown which was embroidered with gold flowers. Her hair was worn in an elegant updo, revealing a pair of the late Queen's diamond drop earrings.
Princess Kate also wowed on the first day of the South Korean state visit. Prince William's wife looked so radiant in a billowing cape dress designed by Catherine Walker, with an oversized neck-tie bow. She coordinated the dress with matching ruby court shoes.
Duchess Sophie also matched Princess Anne and Princess Kate's royal energy. She looked like a vision in a white gown by Suzannah London with a sheer panel from the shoulders to the neck with embroidered delicate flowers.
The state banquet was an evening full of pomp and ceremony. The King was seen wearing a full set of miniature medals, as well as the Garter Star and the Thistle Star, which used to belong to his grandmother, the Queen Mother.
It was also a star-studded occasion. K-pop stars Blackpink and Birmingham City footballer Cho So-hyun were in attendance when the King gave a speech to acknowledge Korea's younger generation for their environmentalism.
"I applaud Jennie, Jisoo, Lisa and Rosé, better known collectively as BLACKPINK, for their role in bringing the message of environmental sustainability to a global audience as Ambassadors for the U.K.’s Presidency of COP 26, and later as advocates for the U.N. Sustainable Development Goals," HRH said.