"Beautiful Beatrice turned 30." Eugenie wrote next to the snap.
The pair revealed to Vogue magazine that they are each other’s rock.
"One of the biggest fights we ever had was about a pair of Converse trainers," revealed Beatrice. "We have the same size feet and both of us had identical pairs. One pair got trashed and the other sister may have swapped them."
The pair were last seen out on Christmas Day when they joined the rest of the royal family in Sandringham for the annual Christmas Day service.