The royal family Instagram account is getting ahead of the festivities and just shared Duchess Sophie's portrait before her birthday on Monday. However, there's one tiny detail that I almost missed—and it has nothing to do with her photos.

It’s a milestone birthday for Duchess Sophie, who officially rang in the special day on January 20 with a little more pomp and circumstance than usual, courtesy of an official new portrait and plans for a major birthday celebration at their Berkshire home Bagshot Park.

Along with The King and Queen Camilla, Prince William and Princess Kate, who share a close bond with the Edinburghs, are said to be joining the festivities. The Princess of Wales and Duchess of Edinburgh are said to have a particularly strong relationship, with Kate viewing Sophie as a sort of "royal sister."

Sophie, the Duchess of Edinburgh is marking a milestone birthday! She turned 60 on Monday, Jan. 20, and friends and former colleagues have been honoring her contribution to the royal family – amid the release of the duchess' stunning new portrait.

The royal family has wished the Duchess of Edinburgh a very happy 60th birthday. Sophie’s milestone was celebrated on the British monarchy’s official social media accounts with a video montage of photographs of the duchess on royal engagements,

Duchess Sophie turned 60 on Jan. 20, and the Royal Family released a new portrait in honor of the momentous occasion. London-based fashion photographer Christina Ebenezer created Duchess Sophie's beautiful new portrait.

Sophie, the Duchess of Edinburgh is turning 60 in style. The royal—who marked her milestone birthday on Monday, January 20—released a trio of stunning portraits to commemorate the special occasion over the weekend that seemingly included a subtle sartorial nod to her grand new title.