When the royals are in the privacy of their own home, surrounded by just their nearest and dearest, they don't call each other by their titles.
Many have their own nicknames for each other, with Meghan Markle revealing that she calls her husband Prince Harr, Haz during an unprecedented 'tour of LA' interview with James Corden.
The Queen's immediate family have called her Lilibet for years and Prince William would refer to her as 'Gary' when he was younger as he couldn't say 'grandma'.
And the youngest generation of royals also use cute names for their elders.
Prince George, Princess Charlotte and Prince Louis are said to know everything about 'Granny Diana' and refer to the Prince of Wales as 'Grandpa Wales'.
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According to the Daily Mail, the nickname Grandpa Wales follows the same format as the Queen used for her grandad George V, who she referred to as Grandad England.
But when it comes to Camilla, Duchess of Cornwall, it's apparent that she goes by a different name to the traditional 'grandma' or 'nanny.'
Camilla, who has five grandchildren of her own, plus the Cambridge kids and Prince Harry and Meghan Markle’s Archie and Lili, is referred to as 'Gaga'.
According to the Sun, Camilla told Lady Gaga that her step-children called her 'GaGa' when they met during the 2016 Royal Variety Performance.
Shortly after the birth of Prince George, the Duchess told the Daily Mail: "My own grandchildren call me GaGa.
"I don’t know if it’s because they think I am! It is funny but is still very sweet."
Meanwhile, Prince George is also said to have an adorable nickname for his great-grandmother, the Queen, and calls her "Gan-Gan".
Speaking back in 2016 after the birth of Princess Charlotte, Kate Middleton said: "It's very special having a new little girl…I feel very, very lucky that George has got a little sister.
"The Queen was really thrilled that it was a little girl, and I think as soon as we came back here to Kensington she was one of our first visitors here.
"George is only two-and-a-half and he calls her 'Gan-Gan.'
"She always leaves a little gift or something in their room when we go and stay and that just shows her love for her family."
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