Princess Diana thought joining the royal family was like ‘playing with grown-ups’

In the weeks following her July 1981 marriage to the future King Charles III, Princess Diana sounded happy and hopeful as she adjusted to life inside the monarchy.

A newly surfaced handwritten letter from Diana to former school friend Katherine Hanbury offers a revealing glimpse into the late Princess of Wales’ mindset at the start of her marriage — years before the fairy tale unraveled.

In the candid note, which she wrote while staying at Balmoral Castle in Scotland in September 1981, Diana reflected on what life felt like being wed to the future monarch, who was then still known as Prince Charles.

The intimate letter, now heading to auction as part of a collection of Diana memorabilia, captures the newlywed sounding playful and unguarded as she acclimated to the pressures of being The Firm’s newest member.

“It’s a case of playing with grown-ups!” Diana wrote to her friend.

Young bride, older groom

Diana was just 20 when she married 32-year-old Charles at St. Paul’s Cathedral in London.

Their significant age gap drew attention years before their marriage publicly disintegrated, but during their engagement interview — Diana was still a teenager at the time — neither appeared particularly concerned by it.

“I think Diana will keep me young, apart from anything else,” Charles said in the sit-down, as reported by The Guardian in 1981. “I think I shall be exhausted. … I haven’t somehow thought about it. I mean, it’s only 12 years, and lots of people have got married with that sort of age difference. I just feel you are as old as you think you are.”

Diana similarly brushed off questions about their ages, saying simply, “I have never thought about it.”

Her letter to her friend, however, hints at the reality of stepping into a royal institution dominated by older, more experienced figures while she was still barely out of her teens. At the same time, the note also showed Diana sounding optimistic about married life. “It’s wonderful being married — I think it’s safe to say that after two months…!” she wrote.

Before the drama

The letter also paints a picture of Diana before fame, pressure and heartbreak transformed her public image. In the note, she fondly recalled her honeymoon with Charles aboard the Royal Yacht Britannia that saw them head off on a 12-day Mediterranean cruise.

“We had a blissful honeymoon with endless sun and luckily calm seas,” she wrote.

“I adore being outside all day & hate London! We’re now up in Scotland until the end of October, which is a big treat for us!” she continued.

The collection, which also includes rare school photographs of Diana alongside classmates including Academy Award-winning actress Tilda Swinton and filmmaker Joanna Hogg, is expected to fetch between $5,000 and $8,000 when it goes to auction with Gorringe’s Fine Art & Interiors on July 7.

The timing of the auction coincides with what would have been the 45th anniversary of Diana’s wedding to Charles.

Albert Radford, books and manuscripts specialist at Gorringe’s, described the archive as “a rare glimpse of Diana, Princess of Wales, before duty and fame had the final say.

“Through our client’s recollections from West Heath Girls’ School, Diana comes across as deeply unassuming and domestically minded; someone whose real ambition was simply to have a family and take pride in ordinary things,” Radford said, according to The Telegraph.

“She remembers Diana volunteering to clean the house of the headmistress, and it is memories like this and the collection that has come to light, that present the real young Diana in a way that is completely at odds with the public persona that was created by others.

“She appears here as a young woman suspended between love and history — hopeful, unguarded, and not yet entirely claimed by the institution that would come to define her,” he added. “In these small, fragile traces, innocence lingers — along with a quiet, stubborn belief in something as simple and elusive as love.”