Princess Diana’s brother has given royal watchers a rare and deeply personal glimpse at the future princess before the world knew her name.

Charles Spencer, the younger brother of Diana, Princess of Wales, shared a never-before-seen childhood photo of the beloved royal on Instagram on July 8, showing the siblings as children playing outside on a backyard swing set in 1966.

The sweet throwback shows Charles, then just 2 years old, sitting on a wooden swing while clutching the chains and looking down at his legs. He is seen wearing puffy blue bloomers and a white T-shirt, with golden-blond hair that looks strikingly similar to the style he still wears six decades later — though today, the 9th Earl Spencer’s hair is completely white.

Beside him is a 5-year-old Diana, long before she became one of the most famous women in the world. The future Princess of Wales is seen playing on the red metal bars of the swing set while wearing a blue-and-white floral leotard. Her blond hair is cut into a short bob with straight-across bangs, giving the image a charming mid-century feel years before Diana would become known for her glamorous royal style and iconic pixie cut.

Charles, now 62, kept the caption simple, writing, “Summer moment, 60 years ago.”

But while his note was short and sweet, the response from fans was anything but casual.

The emotional post quickly stirred up memories of Diana, who remains beloved nearly three decades after her tragic death. Commenters flooded the post with heartfelt messages about the late princess and the Spencer family.

“What seems to be a strong Spencer trait: courage,” one person wrote. “True courage. You both have it.”

Another fan reflected on Diana’s lasting place in people’s hearts, writing, “Still hear her name mentioned most weeks in 2026.”

The reaction was yet another reminder of just how powerful Diana’s legacy remains, something Charles has spoken about before.

During a 2025 interview with Good Morning Britain, host Richard Madeley asked Charles how alive Diana remained in his memory, 27 years after she died in Paris.

“Yes, and in so many people’s,” Charles replied. “I mean, even when I was in makeup just now, somebody came up almost crying, saying how much that she meant to them. And every day, people tell me what an inspiration she was, how much they miss her, and what they did on the day she died. It’s extraordinary.”

Diana died at just 36 years old from injuries she suffered in a catastrophic car crash inside the Pont de l’Alma tunnel in Paris in 1997.

When Madeley asked Charles how time changes grief nearly three decades later, he gave a raw answer.

“Yes, well, I think, I mean, I’m sure everyone watching this program has had trauma in their family at some point,” Charles said. “And, like everyone else, you sort of get used to it, without it ever going away.”

The childhood photo arrived just six days before Diana would have turned 65, making the tender image even more poignant for royal fans.

The post also came during a meaningful stretch for Charles personally. On May 15, he married his fourth wife, podcaster Cat Jarman, in an intimate ceremony in Arizona. During the milestone, he reportedly felt the absence of his late sister.

The Spencer family moment also comes as Diana’s younger son, Prince Harry, made a solo return to the United Kingdom.

Diana and her former husband, Prince Charles — now King Charles III — had two sons together: Prince William, now 44, and Prince Harry, now 41. Harry has lived in the United States with his wife, Meghan Markle, since 2020 and only makes occasional trips back to Britain.

The Duke of Sussex returned to London on July 6 for a week of charity-related engagements, including an appearance connected to the Invictus Games Foundation.

For many royal watchers, Charles Spencer’s rare photo was more than just a sweet family memory. It was a heartbreaking reminder of Diana as a little girl on a summer day — decades before fame, heartbreak, palace drama and tragedy made her one of the most unforgettable figures in modern royal history.