According to Nicky, who spoke on The Third Act podcast, Harry phoned the monarch and told her: "We want to call our daughter after you, Granny,' and she said, 'Oh how charming, thank you,' thinking it will be Elizabeth. So, he got permission, but they didn't say the name."
WATCH: Duke and Duchess of Sussex share photo of Lilibet at picnic
Lilibet was the monarch's childhood nickname, short for Elizabeth, and the only family members to call her by the sweet moniker were her parents, the Queen Mother and King George VI, and her late husband Prince Philip.
The nickname is said to have come about when a young Queen, then Princess Elizabeth, couldn't pronounce her name so she called herself 'Lilibet' instead.
The Queen as a toddler in 1927
Her parents and grandparents soon took up the sweet name, and the Queen's father was once quoted as saying: "Lilibet is my pride. Margaret is my joy."
In one thank you note to her grandmother, Queen Mary, the young Queen wrote: "Darling Granny. Thank you very much for the lovely doll's house. I do love it, and I have unpacked the dining room and the hall. Love from Lilibet xxx."
The Queen at her christening, age one month
Meghan and Harry welcomed their daughter Lilibet on 4 June 2021, announcing in a statement: "It is with great joy that Prince Harry and Meghan, The Duke and Duchess of Sussex, welcome their daughter, Lilibet "Lili" Diana Mountbatten-Windsor, to the world."
Explaining their choice of name, they added: "Lili is named after her great-grandmother, Her Majesty The Queen, whose family nickname is Lilibet.
"Her middle name, Diana, was chosen to honour her beloved late grandmother, The Princess of Wales."
There are many nicknames in the royal family, several with adorable stories behind them.
The Duchess of Cambridge was nicknamed "Squeak" as a young girl at St Andrew's School in Berkshire. She explained how the name came about while on a visit to the school years later. "I was nicknamed Squeak just like my guinea pig," she said. "There was one called Pip and one called Squeak because my sister was called Pippa and I was Squeak."
Meanwhile, Duchess Kate's daughter Princess Charlotte is called 'Lottie' by her mother.
Mummy blogger Laura-Ann chatted to the Duchess during the royal's visit to Windsor Park stadium, later writing on her Instagram Stories: "So then she asked how old Bertie is, and I said he is four and she said, 'Oh he's the same age as Lottie' - Charlotte, she calls her Lottie!"
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