The card features a black border, which is used by members of the royal family on stationery during periods of mourning

Prince Charles chose a sentimental photo of his father Prince Philip to thank fans for their outpouring of support in the wake of the Duke of Edinburgh's death.

Instagram user Lise M shared a thank you card she received from Prince Charles' office after sending him a note of condolences following Prince Philip's death on April 9. The letter contained a black and white image from 1958, which showed a young Charles riding with his father in a small motorboat at Cowes, Isle of Wight.

"The Prince of Wales thanks you so much for your very kind message of sympathy," the accompanying message read. "His Royal Highness has been enormously touched by the many generous messages that have been received in recent days; they have provided great comfort at this very sad time."

It concluded, "The Prince of Wales sends you his warmest thanks and best wishes."

Prince Phillip and Prince Charles
Prince Philip and Prince Charles
| Credit: PA Images via Getty
Prince Philip, Duke of Edinburgh and Prince Charles, Prince of Wales
Prince Philip and Prince Charles
| Credit: Mark Cuthbert/UK Press via Getty Images

The card features a black border, which is used by members of the royal family on stationery during periods of mourning.

Queen Elizabeth broke with this tradition in the wake of her husband of 73 years' death. Unlike other current family members and royals before her, she did not used black-edged stationery during the official mourning period. It was confirmed that she will instead use personalized stationery featuring her crest in black instead of the customary red.

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The nod of modernity was perhaps in honor of Prince Philip, who famously had a no-fuss attitude in life and also in death. Designing his own funeral, his coffin was placed onto the back of a Land Rover and the ceremony, held at Windsor Castle on April 17, was without a eulogy.

The Funeral Of Prince Philip, Duke Of Edinburgh Is Held In Windsor
Prince Charles leads the funeral procession
| Credit: Adrian Dennis/WPA Pool/Getty Images

In a video message released the day after Prince Philip's death at age 99, Charles said that he believed his father "would have been amazed" by the outpouring of love and support.

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"My dear Papa was a very special person who I think above all else would have been amazed by the reaction and the touching things that have been said about him and from that point of view we are, my family, deeply grateful for all that," the eldest child of Prince Philip and Queen Elizabeth said. "It will sustain us in this particular loss and at this particularly sad time."