Sophie, the Duchess of Edinburgh posed for a new portrait for her 60th birthday, and photographer Christina Ebenezer is sharing an unseen picture.

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.

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.

Ahead of Duchess Sophie's 60th birthday this month, Buckingham Palace have released a new series of stunning photos of her - and as well as her beautiful outfits, there was one other thing that stood out to royal fans.

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.

I love how she is not afraid to try new things and she makes beautiful choices,” designer Suzannah Crabb of royal favorite Suzannah London tells PEOPLE