This is what Princess Diana used to call the Queen

The royal family, just like us, like to use terms of endearment for their close friends and family. Princess Diana had a sweet nickname for Prince Harry, Duchess Meghan and Harry have the most millennial names for each other, and Prince Harry also has a cute nickname for Kate Middleton.

And it turns out even the Queen has monikers, even though official protocol dictates she be called 'Your Majesty', until you form a personal enough relationship that could you can upgrade to 'Ma'am'.

In public, Prince William and Prince Harry still call her Your Majesty, but in private they call her Granny, and her great-grandchildren call her Gan-Gan.

However Princess Diana had a very familiar nickname for the Queen, even after her divorce to Prince Charles.

She apparently used to call her Mama, a sign of their close relationship, and a moniker that Her Majesty's other daughters-in-law also use.

In fact, Sophie Countess of Wessex, Prince Edward's wife, called the Queen 'Mama' at a recent event, and Catherine Duchess of Cambridge is also said to use the nickname.

There were also rumours Meghan Markle would follow suit as she became closer to Prince Harry's grandmother, but we haven't heard her use the term publicly yet.