Princess Anne’s nickname for King Charles is rather unusual, though it could be seen to reflect their close sibling bond.

We might only rarely hear the royals use their nicknames for each other in public, but they’re understood to have several for family members. From the Princess of Wales calling Prince Louis "Lou-bugs" over the coronation weekend, to the late Queen Elizabeth’s childhood moniker, Lilibet, that Prince Philip used to call her, they are often linked in some way to their first names. However, this isn’t always the case and Princess Anne’s nickname for her big brother King Charles is not only unusual but incredibly adorable. She was heard using it in the BBC’s 2023 documentary, Charles III: The Coronation Year, as she came face-to-face with His Majesty back at Buckingham Palace after the magnificent service.

In the behind-the-scenes footage the Princess Royal remarked, "Hello, Old Bean", much to the delight of King Charles. The monarch laughed and took his younger sister’s hand and kissed it in greeting.

It might sound unusual to hear him referred to in this way, but Princess Anne’s nickname for King Charles highlights their unique royal relationship and closeness. Speaking recently in an YouTube video episode of The Telegraph’s Royal Insight, the publication’s Royal Editor Hannah Furniss reflected on Princess Anne using the 'Old Bean' nickname and how the senior royal has such a significant bond with the King.

"There was a lovely moment in the documentary recently where we saw her calling Charles 'Old Bean'. They have this very warm relationship and she is probably in a better position than anyone to give him advice, give him a bit of sympathy when he needs it, give him a bit of a pep talk," Hannah claimed. "She understands how the Royal Family works and she has a bit of an eye to the past and to the future."

Given her immense importance as a senior royal and potential advisor to King Charles, it’s perhaps less of a surprise that she has such a touching and personal nickname for him. Calling him "Old Bean" is endearing and perhaps highlights his position as her beloved older brother.

King Charles and Princess Anne are the oldest of the late Queen Elizabeth’s children and are just under two years apart in age, compared to Prince Andrew who is 10 years younger than his sister and Prince Edward who is 14 years younger. The King and Princess Royal’s shared experience growing up together is something Hannah believes could have cemented their close bond. 

She said, "They’ve grown up together, they spent their childhood together when the Queen and Prince Philip were travelling a lot. They’re very close."

The royal expert also described Princess Anne as a "big part of the royal ecosystem" and explained how her unwavering dedication has meant she’s a real "right-hand woman" to the King.

"Princess Anne is a key part, perhaps the key part, actually, of the wider supporting family who do these day-to-day engagements, travel up and down the country, travel round the Commonwealth, doing the plaque unveiling, the ribbon cutting. She’s also personally to [King] Charles a real sounding-board and a right-hand woman," Hannah declared.

This was reflected literally in the group coronation portrait taken by Hugo Burnand last year. The Princess Royal stood directly next to King Charles on his right side which was possibly a sign of her key position within the Royal Family and His Majesty’s immense trust in her.