King Charles is slowly replying to the hundreds of thousands of condolences letters he received following the Queen's death on 8 September – and on Wednesday, one royal fan revealed the photo he has chosen for his Thank You cards.
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Taking to Twitter, one user, known as RoyalsOther, shared two photos of the card received. "First post received with the new royal cypher," she wrote.
WATCH: Prince Charles talks about fun childhood with Prince Philip
The card shows the King's new cypher on the front page whilst inside features a beautiful photo of a young Charles with his mother, then Princess Elizabeth, looking out of a window at Balmoral, the late Queen's favourite royal residence.
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The photo was taken by Lisa Sheridan on 28 September 1952, when Charles was nearly four years old.
King Charles chose a picture taken when he was nearly four years old at Balmoral
On the right-hand side, a message reads: "It was so very kind of you to send me such a wonderfully generous message following the death of my beloved mother. Your most thoughtful words are enormously comforting, and I cannot tell you how deeply they are appreciated at this time of immense sorrow."
The letter was signed "Charles R".
Charles has often spoken out about his childhood. Back in 2021 he recalled fun memories alongside his late father, Prince Philip, for the BBC One programme, Prince Philip: The Royal Family Remembers.
Another photo from the same sessions shows a young Charles climbing a wall to get to his mother
"He was marvellous at arranging silly games. I mean, the fun of having obviously young parents was… there were lots of chasing around and mad things," he said in a clip.
In another shared by the royal family's social media accounts, Anne, 72, recalls fishing with her father in Scotland, saying: "I always said I couldn't catch anything and he'd say, 'Nonsense, come with me.' And after I had been casting for about half an hour, he said, 'I see what you mean.' And I just knew it was something I could never do."
In more archive footage, a young Prince Edward can be seen getting into a rowing boat with his father, willing him to "get in".