The Royals are known for their endearing nicknames, from the late Queen Elizabeth II's 'Lilibet' to Princess of Wales ' affectionate term for her youngest son Prince Louis, 'Lou-bugs'.
However, one nickname that stands out is the one used by Princess Anne, 73, for her elder brother King Charles, 75. This was revealed in the 2023 documentary, Charles III: The Coronation Year, where she greeted her brother at Buckingham Palace post-coronation with a jovial "Hello, Old Bean."
Charles responded with laughter and a kiss on Anne's hand.
This unusual nickname is believed to reflect the close bond between the siblings, who are the eldest children of the late Queen Elizabeth II and Prince Philip and share an age difference of just two years.
Their younger brothers, Andrew, 64, and Edward, 60, are significantly younger, which meant that Anne and Charles shared many childhood experiences together, strengthening their bond, reports OK!.
Hannah Furniss, The Telegraph's Royal Editor, discussed Charles and Anne's relationship in a YouTube video of the publication's Royal Insight, stating: "They've grown up together, they spent their childhood together when the Queen and Prince Philip were travelling a lot. They're very close."
Hannah also spoke about Anne's nickname for Charles. She said it demonstrates that they have a "very warm relationship" and that Anne is a huge support to the King, who may turn to his sister when he needs a pep talk.
"There was a lovely moment in the documentary recently where we saw her calling Charles 'Old Bean'," she said.
"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.
"He understands how the Royal Family works and she has a bit of an eye to the past and to the future. "The Royale expert went on to describe the Princess Royal as a "big part of the Royal ecosystem" and said Anne's dedication to the Firm means she's a "right-hand woman" to King Charles.