“🧸 THE ADORABLE ENDEARMENT THAT ACCIDENTALLY EXPOSED KATE AND CHARLES’S DEEP FAMILY BOND.” This isn’t a code name or a formal title; royal insiders and biographers have confirmed that Kate affectionately calls the King “Grandpa” behind closed doors. While the world sees King Charles III as the formal head of state, to Catherine and her three young children, he is simply the warm patriarch of their household. The secret moniker was actually caught on camera once before during a high-profile gathering, where sharp-eared observers noticed her greeting him with a warm kiss and a casual, loving phrase. This sweet clue beautifully highlights just how normal they try to keep family life when the cameras are turned off. tt

Princess Kate’s precious nickname for King Charles behind closed doors revealed

The Princess of Wales met her future father-in-law during her first visit to Balmoral and they have maintained a close bond ever since

London - 16.09.25
Members of the Royal Family attend a Requiem Mass catholic funeral service for The Duchess of Kent at Westminster Cathedral. Katharine, Duchess of Kent, wife of Prince Edward, Duke of Kent, died on September 4 at the age of 92.
Pic: © Max Mumby
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The Princess of Wales and her father-in-law, King Charles, have an incredibly close bond. But did you know Kate has the sweetest nickname for her father-in-law behind closed doors? Before you find out, why not have a go at our fun royal nickname game, where you have 60 seconds to match the royal to their moniker. If you are viewing this article on a non-Hello! platform, click here to play the game.

Royal expert Richard Jobson previously reported in The Daily Mail that Kate calls Charles ‘Grandpa,’ according to a courtier. His Majesty is known to have a couple of affectionate names for his daughter-in-law, including ‘beloved daughter-in-law’ and ‘darling daughter-in-law.’ According to the report, he always greets her with a “loving kiss.”

King Charles kisses Britain's Princess Kate as they arrive for the World Premiere of the James Bond 007 film No Time to Die in 2021© CHRIS JACKSON
The pair have always had an incredibly close bond

In April 2024, a source told HELLO! that while the pair have always shared a close relationship, the bond between them grew as they turned to each other for comfort during their respective cancer diagnoses and treatments.

The King paid Kate a bedside visit when they were both staying at the London Clinic, and the pair shared a private lunch in Windsor the day before she revealed her cancer diagnosis to the world in March.

Robert Hardman, author of Charles III, also explained: “It’s very clear that he’s extremely concerned about her. I think he wants to make sure as much as he can that if there’s anything he can do, he will do, because for a very fit and healthy young mother, this is a different order of magnitude than someone having to deal with this in their 70s.

“I’m sure he’s been a source of comfort for her in the same way she’s probably been a source of comfort for him,” he adds. “I think it cannot but have brought them even closer together. He’s always had a huge regard for his daughter-in-law. He thinks she’s just wonderful.

“When people are in the hospital, they don’t really want a fuss. But the fact was: the King was there, she was there, and the Queen was there with him as well. And they did go around to check and reassure the Princess.

Charles is incredibly fond of his "beloved daughter-in-law"© RICHARD POHLE
Charles is incredibly fond of his ‘beloved daughter-in-law’

“It’s a reminder that the Windsors are mortals like the rest of us. And we have to have great sympathy with the fact that they are undergoing an absolute shock of a lifetime, except they’re having to undergo it with all of us talking about it.”

Close bond

In his book Catherine, The Princess of Wales, he wrote that King Charles’ eyes visibly “light up” when the Princess of Wales enters the room, and that “they always make a bee-line for each other”.

Charles and Kate have become even closer since news of their cancer diagnosis and treatment© WPA Pool
Charles and Kate have become even closer since news of their cancer diagnosis and treatment

Kate has also helped bring William and his father closer together, according to the royal biographer. “An instinctive peace-maker, she has smoothed the way for William and his father to have a better relationship than they had in the past,” he divulged.

First meeting

It seems that Charles and Kate set off on the right foot from the very beginning. Back in 2010, during the Princess’ official engagement interview alongside her now-husband, she mentioned how well her first meeting with the King went. “I was quite nervous about meeting William’s father, but he was very, very welcoming, very friendly. It couldn’t have gone easier, really, for me.”

Queen Camilla, King Charles III, Prince William, Prince of Wales and Catherine, Princess of Wales pose for a photograph ahead of The Diplomatic Reception in the 1844 Room at Buckingham Palace on December 05, 2023© Getty Images
Kate has also helped bring William and his father closer together

Pressed about the pressure of meeting her future husband’s grandmother, the late Queen Elizabeth, Kate said: “I first met her at Peter and Autumn’s wedding and again it was amongst a lot of other guests and she was very friendly.”

William added: “She was very welcoming. She knew it was a big day and everything was going on with Peter and Autumn. She wanted to meet Kate for a while, so it was very nice for her to come over and say hello.”