It was also revealed that the Queen's security detail uses a surprisingly common name to refer to her.
Her security officers call her “S” for safety when she is doing engagement, instead of calling the Queen by her real name.
According to News.com.au, an aide revealed the code name during a reconnaissance security trip ahead of a royal visit to a cathedral town.
“She’s written down as S,” he allegedly said.
When asked what the “S” stands for, he was said to have cupped his hand over his mouth and whispered: “It’s Sharon.”
Royal historian Hugo Vickers also said it was “highly likely” that the common name is being used for her Majesty.
“The purpose of any sobriquet is that it should be anonymous and memorable,” he told the publication.
“If it can also be a bit mischievous and therefore all the more memorable, then that makes sense.
“Although S might simply stand for sovereign of course.”
According to News.com.au, the Queen also goes by another name when she is in private around her family.
Her great-grandkids, Prince George and Princess Charlotte, refer to the monarch as “Gan-Gan,” while her grandson Prince William referred to the Queen as “Gary” when he was too young to pronounce “Granny.”
The Netflix drama The Crown reveals that Prince Philip refers to the Queen as “Lilibet” and “sausage.”
WATCH: Prince Philip SNAPS at photographer 'Just take the f***ing picture'
Other members of the royal family also have nicknames.
Prince George and Princess Charlotte refer to Camilla Parker-Bowles as Gaga (The Duchess of Cornwall reportedly informed Lady Gaga of this at the 2016 Royal Variety Performance).
According to the Mail on Sunday, Meghan Markle has also been given the nickname “Tugsten” by Prince Charles.
The source told the publication that “Prince Charles admires Meghan for her strength and the backbone she gives Harry, who needs a tungsten-type figure in his life as he can be a bit of a softy. It's become a term of endearment.”