Kate Middleton is good as gold.

The Princess of Wales looked radiant at the state banquet at Windsor Castle Tuesday night, wearing a bright yellow keyhole Elie Saab gown.

The pleated look ($6,500) features a braided neckline, a transparent cape and was part of the brand’s spring/summer 2025 collection.

She chose one of her her go-to crowns, the Queen Mary’s Lover’s Knot Tiara, which was said to be Princess Diana’s favorite, as well. The piece features teardrop-shaped pearls and was last worn by the late Diana in 1991 before Middleton picked it back up in 2015.

Middleton paired the pieces with the Greville diamond chandelier earrings and Queen Mary’s diamond choker bracelet along with a gold glitter Anya Hindmarch clutch and Aquazzura gold sequined pumps.

The princess, of course, also donned her badge, sash and star of the Royal Victorian Order, as is customary for state dinners.

Earlier in the day, Middleton welcomed the Sultan of Oman, Sultan Haitham bin Tarik al Said, to the UK while dressed in a bespoke hunter green Alexander McQueen coat with a black lace turtleneck top.

With a matching fascinator and classic quilted leather Chanel flap bag in one hand, Middleton accessorized with another historical piece of jewelry: the Queen Alexandra Three Feathers Brooch.

Made of diamonds, rubies and emeralds, it is set in gold that was originally mined in Merionethshire, a county in North Wales and features a small motif of a trio of ostrich feathers with the motto “Ich dien,” translated from German, meaning, “I serve.”

The feathers are surrounded by a circle of larger diamonds and there is an emerald drop that can be attached or detached to the base.

On this particular occasion, the princess chose to wear the drop, which complemented the overall color of her look. Green is also one of Oman’s national colors, which makes it all the more symbolic.

The brooch was originally designed and crafted in 1863 by the royal jeweler Garrard. It was given to Queen Alexandra in 1863 by the Ladies of North Wales — a committee of women who raised funds to purchase the piece of jewelry as a wedding present.

It is traditionally worn by the woman married to the Prince of Wales, independent of generation or title. As such, it’s been worn after Queen Alexandra by Queen Mary of Teck, Princess Diana, Queen Camilla and — now exclusively — Princess Kate.

And, as antique jewelry boasts a special penchant for the ability to transform, this particular brooch can be worn as both a pin as well as a necklace — a form in which the late Diana had been seen wearing it.

The brooch is a particular favorite of Middleton’s, as she’s chosen it on multiple occasions since coming into ownership of the diamond piece in 2022.

And, while the princess often opts for new, affordable jewels, it’s always such a treat to see her reach into the vast royal archives for a deep dose of jewelry history.