Meet Princes William and Harry's secret step-sister

Wait what?

We thought we knew everything about the royal family.

From the hilarious nickname Prince Philip has for Queen Elizabeth down to her Majesty's favourite song (SO appropriate btw) it seems like there isn't anything we don't know about the life of Liz.

We're even clued up on the lives of the extended royal family, from what Meghan Markle eats to get flawless skin to the surprising reason why Kate Middleton never goes anywhere without a clutch bag.

But it turns out there is a pretty big fact about Princes William and Harry that we had NO idea about.

Yep, apparently Prince William and Prince Harry have a step-sister called Laura.

Laura Lopes is the daughter of Camilla Parker Bowles, but ever since Camilla married Prince Charles in 2005 she decided to keep her out of the public eye.

Laura also has a brother (which means Wills and Harry also have a step-brother) called Tom, who is a food author and journalist.

The two are the children of Camilla and Andrew Parker Bowels, who divorced in 1995.