Royal Fiancée Harriet Sperling Is Following in Princess Diana's Footsteps During Balmoral Vacation

Peter Phillips and Harriet Sperling smiling and wearing sunglasses — (Image credit: Getty Images)

Balmoral Castle has served as more than just the beloved retreat of Queen Elizabeth, King Charles and the rest of the Royal Family—the estate has also presented newcomers to the royal fold with an unspoken initiation known as the "Balmoral Test." Viewers of The Crown are familiar with the tradition, as dramatized in Season 4 of the Netflix hit when Princess Diana made her first visit to the Scottish castle. The so-called Balmoral Test isn't written down anywhere, but those who have faced it know the stakes: impress the family in their favorite setting, or risk being deemed unsuitable.

Princess Diana won over the Windsors when she first arrived at Balmoral in the summer of 1980. Even though she'd later grow to hate trips to Scotland, the shy nursery school teacher passed the Balmoral test by showing her humor during games and country pursuits. Fast forward to 2025, and Peter Phillips's new fiancée, Harriet Sperling, is facing the same initiation as she's joined the Royal Family during their annual Scottish vacation for the first time.

At age 45 compared to Diana's 19, Sperling has experience and a year of events with the Royal Family on her side. The NHS nurse has attended everything from Royal Ascot to Wimbledon since she first started dating Princess Anne's son last spring, and King Charles even gave her a coveted spot in the carriage procession at Ascot this summer despite the fact the couple wasn't yet engaged.

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Harriet Sperling and Peter Phillips waring sunglasses smiling at each other — Harriet Sperling and Peter Phillips—seen at the Wimbledon 2025 championships— are visiting Balmoral together for the first time.

Harriet Sperling wearing a white dress next to Peter Phillips, standing against a white fence — The couple confirmed their engagement on August 1.

Prince Charles and Princess Diana leaning on a bench at Balmoral wearing sweaters — Princess Diana is pictured at Balmoral with Prince Charles ahead of their 1981 wedding.

"Everyone knows Peter is smitten and his family have accepted Harriett into the set up so she will likely pass the infamous Balmoral Test with flying colours," a source told the Sun.

Per the outlet, Sperling has been spending time with future sister-in-law Zara Tindall and Zara's kids "on electric-powered mountain bikes around the estates" and has also gone horseback riding with the family at Balmoral.

Phillips and Sperling announced their engagement on August 1, with a statement reading, "Mr Peter Phillips, the son of HRH The Princess Royal and Captain Mark Phillips and Ms Harriet Sperling, daughter of the late Mr Rupert Sanders and Mrs Mary Sanders of Gloucestershire, have today confirmed their official engagement."

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Kristin Contino is Marie Claire's Senior Royal and Celebrity editor. She's been covering royalty since 2018—including major moments such as the Platinum Jubilee, Queen Elizabeth II’s death and King Charles III's coronation—and places a particular focus on the British Royal Family's style and what it means.

Prior to working at Marie Claire, she wrote about celebrity and royal fashion at Page Six Style and covered royalty from around the world as chief reporter at Royal Central. Kristin has provided expert commentary for outlets including the BBC, Sky News, US Weekly, the Today Show and many others.

Kristin is also the published author of two novels, “The Legacy of Us” and “A House Full of Windsor.” She's passionate about travel, history, horses, and learning everything she can about her favorite city in the world, London.