EXCLUSIVE: Princess Catherine and King Charles' Secret Family Nicknames for Each Other Revealed
The king and his daughter-in-law appear to have a close bond.
Oct. 18 2026, Published 4:00 p.m. ET
Princess Catherine and King Charles have developed a highly affectionate relationship behind palace doors, with the future queen said to have taken to calling her father-in-law "Grandpa" while he affectionately addresses her as his "darling daughter-in-law."
Sources have told RadarOnline.com the Princess of Wales, 44, and Charles, 77, have established a close family bond that contrasts with the formality surrounding their public roles.
Princess Catherine affectionately calls King Charles 'Grandpa' behind closed doors.
And royal author Robert Jobson, 62, has revealed the private nicknames the pair apparently use for each other in his biography Catherine, the Princess of Wales, while describing how the monarch regularly greets Catherine with a kiss and enjoys exchanging jokes with her during family gatherings.
According to Jobson, the warmth between the pair reflects Charles' considerable admiration for Catherine and the important role she has assumed within the royal household.
A Palace courtier quoted in the biography said: "I think (Charles) understands Catherine is a good influence on the entire family. He loves and truly appreciates everything she does."
Princess Catherine Helps Improve Charles and William's Relationship
The Princess of Wales helped smooth relations between the King and Prince William, an author claimed.
The author also credits Catherine with helping improve relations between Charles and his eldest son, Prince William, 44, whose relationship with his father has been turbulent.
Rather than becoming drawn into family disagreements, Catherine is said to have developed a reputation for understanding competing perspectives and encouraging reconciliation within the royal family.
Jobson describes the princess as an "instinctive peace-maker" who has "smoothed the way for William and his father to have a better relationship than they had in the past."
Another source quoted by the author characterized Catherine as someone who prefers resolving tensions through patience and understanding rather than encouraging or indulging in feuds or confrontations.
The insider described her as "somebody who always tries to see both sides of any dispute," adding the "emotionally mature" princess provides a "stabilizing influence."
Shared Cancer Diagnoses Deepen Family Bond
Princess Catherine's cancer diagnosis reportedly deepened her bond with King Charles.
Her relationship with Charles is thought to have become particularly significant following their respective cancer diagnoses in 2024, when both temporarily withdrew from some public responsibilities to undergo treatment.
Charles is still being treated for an undisclosed form of cancer.
Their shared experience brought a new dimension to the pair's family connection, sources tell us.
Charles and Catherine also shared a private lunch shortly before the princess publicly disclosed her cancer diagnosis in a video message in March 2024.
The affectionate nickname "Grandpa" also reflects Charles' relationship with Catherine and William's three children, Prince George, 13, Princess Charlotte, 11, and Prince Louis, eight.
The monarch has frequently demonstrated his affection for his grandchildren during public appearances, although much of their family life remains private.
Princess Catherine's Role Grows as William Plans Royal Changes
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Princess Catherine's royal role grew after her 2011 marriage to Prince William.
Catherine's position within the monarchy has evolved considerably since she married William in April 2011, with the princess increasingly assuming prominent ceremonial and charitable responsibilities.
A source claimed: "Catherine's ability to maintain close relationships across different generations has become an important feature of her standing within the royal family, and will be vital in her future role as queen."
William is set to succeed Charles as king, with the prince thought to favor what sources have told us will be a more "ruthless" approach to the size of the royal family than his father has taken.
Insiders say he will be intent on slimming down the number of taxpayer-funded royals to make the brand "future-proof" for a British public being battered by a growing cost of living crisis.
