Princess Eugenie, 28, captioned the post of herself, Princess Beatrice, 29, Prince Andrew, 58, and Sarah Ferguson, 58, “90s flashback”.
The sweet snap shows the family on board the HMS Cottesmore.
Eugenie and her sister sit on their parents laps, and all four smile broadly for the cameras.
The photo was taken at some point between April 1993 and November 1994, when Andrew was commander of the Royal Navy vessel.
Sarah Ferguson, then the Duchess of York, is seen wearing a black dress with silver disk pattern, and wears her hair in a relaxed half-up, half-down style.
Beatrice and Eugenie are wearing matching white dresses with an HMS Cottesmore waistband.
The picture has received over 21,000 likes and hundreds of comments.
Many royal fans praised Sarah Ferguson, and expressed a wish for her and Andrew to reunite.
One wrote: “Aaaww Beautiful family !! I hope your parents remarry !!”
Another said: “It was great to see your mom at Harry and Meghan’s wedding, she looked wonderful!”
Eugenie is preparing for her October wedding to Jack Brooksbank, 31, after the couple announced their engagement in February.
Their wedding will be held at St George’s Chapel in Windsor – just like Eugenie’s cousin, Prince Harry, 33, who wed Meghan Markle, 36, last month.
Jack and Eugenie attended the wedding, and were sure to be imagining their own special day in a matter of months.
It is expected the entire Royal Family will attend Eugenie’s nuptials, although hers will not be a state wedding, nor will it be televised as Harry and Meghan’s was.
Will Jack get a title after he marries in to the Royal Family like Meghan Markle did?
When Meghan married Harry she became the Duchess of Sussex, as Harry had been named Duke.
However, it is unlikely Jack will follow suit, according to royal expert, blogger and historian Marlene Eilers Koenig.
She told Hello! Magazine: “Jack will not be getting any title from the Queen.”
However, this is not a snub so much as it is a rule set by previous marriages of royal women.
Marlene added: “The precedent was set by Princess Alexandra and the Hon. Mr. Angus Ogilvy in 1963. He turned down an earldom.”
