The Duchess of Cambridge just recently got home from a Caribbean vacation with her family (and seems to be a tad sunburnt!). Her first stop when back in the UK? A fundraising gala at London's National Portrait Gallery, where she is patron.

The event, described as "black tie with a little sparkle," prompted some anticipation among fans of Kate's style, especially after the Queen's recent decree that the Duchess should wear more impressive jewelry. And tonight, she didn't disappoint. Kate wore her midnight blue Jenny Packham gown that we first saw in October of 2013, but kicked it up a notch this time around with a gorgeous, glittering diamond necklace.

When Kate and William attended the Royal Film Performance and the Duchess wore a high-sparkle necklace, there was a collective gasp -- are those all diamonds? We learned quickly that the necklace from that evening was in fact $35 and from Zara (amazing), but tonight's necklace is on an entirely different level. The statement piece, which is on loan for the evening from Queen Elizabeth, was a gift for the Queen's wedding ing 1947. It came from Nizam of Hyderabad, an extremely wealthy King of a state in India, along with a one-of-a-kind tiara. (Um, Kate... where's the tiara..? Why not go all out?!) And yes, this one IS all diamonds... it's priceless.

The thing is, we don't mind that Kate recycles her gowns, tops, coats, etc. -- in fact, we love it. She's mindful of spending, loves to wear accessible brands, and has favorite pieces of clothing like a normal woman. Not to mention good taste, because she looked effortlessly glamorous in the deep blue gown.

Click through the gallery above to see more photos from tonight's gala event, and check back later to see our full recap of the Jenny Packham Fall 2014 collection which just went down the runway today. Plenty of gowns worthy of our favorite royal!