Prince Philip has passed away at the age of 99, after battling health problems for the last few years.
Until now it had remained a cherished family photograph unseen by the rest of the world.
Showing the Queen and the Duke of Edinburgh surrounded by seven of their great-grandchildren at Balmoral Castle, the precious image had been kept under wraps for four years.
Yet Prince Philip's death on Friday last night prompted the 94-year-old monarch to open the treasured royal family album in loving memory of a beloved patriarch.
The image, taken by the Duchess of Cambridge in 2018, shows the Queen holding baby Prince Louis in her arms as she sits between his brother Prince George, now 7, and sister Princess Charlotte, 5.
Peter Phillips's daughter Savannah, 10, their eldest great-grandchild, stands behind the couple as her younger sister Isla, 9, cradles their cousin Lena, 2, the daughter of Zara and Mike Tindall, whose eldest Mia, 7, flanks them, seemingly stifling a giggle.
The Queen and the Duke of Edinburgh surrounded by seven of their great-grandchildren at Balmoral Castle in 2018. Photo / Duke and Duchess of Cambridge
Telling a thousand words about the Queen and the duke's close bond with the youngest members of the House of Windsor, the image captures the relaxed mood as the children visited Great Granny and Grandpa in Scotland that summer.
The picture was taken almost a year before the Duke and Duchess of Sussexes' son Archie, their eighth great-grandchild, was born.
The Duke and Duchess of Cambridge also issued their own separate photograph, taken three years earlier at Balmoral, showing the Queen and the duke posing with an infant George and baby Charlotte, wearing a bonnet.
The post on the Kensington Palace Instagram page read: "Today we share, along with members of @theroyalfamily, photographs of The Duke of Edinburgh, remembering him as a father, grandfather and great-grandfather."
William and Kate are seen along with Prince George and Princess Charlotte in a photo with Philip and the Queen at Balmoral in 2015. Photo / The Duchess of Cambridge
The Prince of Wales also joined the trip down memory lane, posting two images on social media. The first, black and white, shot showed the duke and his then 17-year-old son playing polo together in 1966. Charles passed on his inherited love of the sport to Princes William and Harry.
A second photograph showed Philip with Charles and Camilla, the Duchess of Cornwall, at the Duke and Duchess of Cambridge's wedding in 2011.
The pictures were captioned: "Remembering The Duke of Edinburgh as a much-loved Father and Father-in-Law."
Prince Philip and a young Charles on horseback playing polo.
The charming images were published after Princess Eugenie became the third of the Queen and the duke's grandchildren to pay tribute to their "dearest Grandpa", promising to look after "Granny" in his absence.
In February, she gave birth to the couple's ninth great grandchild, August Philip Hawke Brooksbank. Mrs Tindall gave birth to their 10th last month when Lucas Philip Tindall - also named after the duke - was born on the bathroom floor of the couple's Gloucestershire home last month. Unfortunately, Philip did not manage to meet either of the new additions before he died at Windsor Castle on Friday, aged 99.
Harry and Meghan's second child, a girl, is due this summer.
The great-grandchildren - who are thought to refer to the Queen as "Gan Gan", will not be attending the funeral on Saturday.
As the royals prepare for the ceremony at St George's Chapel, they have been described as a "family in mourning" who are "united" in support of Her Majesty.
