Princess Kate Pulls Off Her Biggest Tiara Surprise Ever in Queen Victoria's Historic Ruby-and-Diamond Circlet and a Dazzling Caped Gown

The Royal Family welcomed Germany's president and first lady to Windsor Castle for an official state visit on Wednesday, December 3, and Princess Kate pulled out all the fashion stops for the glittering state banquet held in the couple's honor. The Princess of Wales wore a Prussian blue coat to welcome their guests earlier in the day, and she kept the blue theme going—and gave a nod to a queen with German ties—for the banquet.

The Princess of Wales stepped out in a blue Jenny Packham gown covered in sequins featuring a dramatic, sheer cape trailing behind her. But the star of the show was the incredible tiara Kate debuted for the banquet.

Fans are used to seeing Kate in Princess Diana's favorite diamond-and-pearl tiara, the Lover's Knot, and she's also worn the Lotus Flower Tiara on several occasions. But I'll admit Queen Victoria's Oriental Circlet Tiara was absolutely not on my bingo card for Wednesday's state banquet.

The diamond tiara has a fascinating history. Queen Victoria's German-born husband, Prince Albert, designed the piece for his wife in 1853, per The Royal Watcher blog. The tiara features a whopping 2,600 diamonds, and although it originally featured opal accents, they were later replaced with rubies by Queen Alexandra since she found opals to be "unlucky."

Most importantly, Queen Victoria marked the tiara as an heirloom of the crown, meaning it would stay in the royal collection for future Queens throughout history—like Princess Kate—to wear it.

As for the rest of her jewelry, the Princess of Wales honored another late Queen by wearing Queen Elizabeth's diamond earrings.

To top the evening off, Kate also posed for the perfect holiday portrait with Prince William, standing in front of a Christmas tree with her husband, who was dressed in the Windsor tail coat. Get those Christmas cards printed ASAP.