It's no secret that when you're a member of the British royal family, there's certain etiquette you have to follow while in public.
Every outfit, appearance, and speech is meticulously planned so that the Queen and the monarchy are represented in the best light.
This also means that as long as the royals are out in public they should be addressed by their official titles.
Calling Queen Elizabeth II and her relatives by their nicknames is greatly frowned upon, and even they themselves avoid doing this among each other while carrying out official duties.
But behind closed palace doors, the royals have some adorable nicknames for each other.
This week, during their visit to Leicester, England, Prince William and Kate Middleton were asked about their three children, five-year-old Prince George, three-year-old Princess Charlotte, and seven-month-old Prince Louis, and they took the opportunity to share some cute details about them.
"They're doing well, thank you," Kate told one fan. "They're getting excited for Christmas time."
She added that George and William played soccer the night before, and the little boy wanted to know if his "pops" would be playing the game again while in Leicester, revealing the affectionate name William has been given by his kids.
Kate and William also have some cute nicknames for each other, according to sources close to the Cambridges.
The duke allegedly calls his wife "poppet," and was heard saying it outside the hospital after the birth of George in 2013.
Like your average couple, the pair have also been heard referring to one another as "darling," and "babe," on several occasions.
William's brother Prince Harry and his wife Meghan Markle also go by unofficial monikers when they're among family and friends.
Harry is "Spike" to his close friends, and to Meghan he is "Haz," according to the Suits star's former rep.
As for Meghan, she often goes by "Meg," but Prince Charles prefers to call her by an unusual name. He calls her tungsten because she is strong like the metal.
"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 softie," explains an insider. "It's become a term of endearment."
Even the Queen can't escape being given an embarrassingly endearing name. Prince Philip calls the Queen "cabbage," after the french pet name "mon p'tit chou."
William and Harry call her "Granny," and the great-grandchildren call her "Gan Gan."
The late Princess Diana used to call Elizabeth "Mama," a name that many believe Meghan will be using now that she's officially a part of the family.