Eugenie and her older sister Princess Beatrice can be seen giving cheeky smiles with their hair up in scrunchies.
Fans couldn't help but comment on the sweet snap.
"Lovely picture!!!" one wrote
"SISTERLY LOVE," another added.
A third quipped, "You remind me so much of me and my younger sister. Early 90s for the win."
Eugenie and Beatrice are the daughters of the Queen's son Prince Andrew, Duke of York, and Sarah Ferguson.