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.

Penny Goldstone

Penny Goldstone is the Digital Fashion Editor at Marie Claire, covering everything from catwalk trends to royal fashion and the latest high street and Instagram must-haves.

Penny grew up in France and studied languages and law at the Sorbonne Nouvelle University in Paris before moving to the UK for her MA in multimedia journalism at Bournemouth University. She moved to the UK permanently and has never looked back (though she does go back regularly to stock up on cheese and wine).

Although she's always loved fashion - she used to create scrapbooks of her favourite trends and looks, including Sienna Miller and Kate Moss' boho phase - her first job was at, sourcing the best deals for everything from restaurants to designer sales.

However she quit after two years to follow her true passion, fashion journalism, and after many years of internships and freelance stints at magazines including Red, Cosmopolitan, Stylist and Good Housekeeping, landed her dream job as the Digital Fashion Editor at Marie Claire UK.

Her favourite part of the job is discovering new brands and meeting designers, and travelling the world to attend events and fashion shows. Seeing her first Chanel runway IRL at Paris Fashion Week was a true pinch-me moment.