This is why the royal family doesn't have a last name.

Madonna. Beyoncé. Adele. The Queen.

They’re all famous faces that are SO ICONIC that they don’t need a last name for people to recognise who they are.

But…if the gang of misfits we know and love as ‘The Royals’ ever needed to use a last name for, say, their driver’s licence, or birth certificate, what do they write?

If you thought the answer was 'Windsor'...well, you'd be just a little bit wrong. So, you should brace yourselves, because the reason why is just a tiny complicated.

It turns out, up until the 1917 the royals didn't even need to use last names at all. They just used their first names and the house or dynasty they were a part of (think House of Tudor).

It was King George V (whose house name was Saxe-Coburg-Gotha) who decided in 1917 to change his last name to 'Windsor', named for one of the royal family's properties, due to anti-German sentiments at the start of World War I.

He also specified that Windsor was to become the official surname of the royal family.

Until 1960, when Queen Elizabeth II decreed the descendants of her and her husband, Prince Phillip, would use the hyphenated surname of Mountbatten-Windsor, a combination of both of their last names.

So that's that settled then, right? Those lovable tots' real last names are surely Charlotte and George Mountbatten-Windsor.

OF COURSE NOT, because any royal with the title of 'His Royal Highness Prince' or 'Her Royal Highness Princess' doesn't even need a surname at all.

It turns out the royals we know and love today have used all sorts of names as their surnames: Prince William and Prince Harry went by William Wales and Harry Wales when they served in the military, because their father, Prince Charles, is the Prince of Wales.

Princesses Eugenie and Beatrice have also been rumoured to use the surname 'York', after their father's title, Prince Andrew, Duke of York.

So, while they're able to use Mountbatten-Windsor as their last name should they desire, they also don't have to follow the laws of the land and can pretty much use whatever last name they please.

And if all that is just complicated, we'll just stick to calling them Harry, William, Kate, Charlotte and George.