Duchess Kate and Prince William have been known as the Duke and Duchess of Cambridge since their wedding.
When the Cambridges are mentioned, everyone knows you're talking about the prince, his wife and their children George, Charlotte and Louis. But Kate very nearly missed out on her now well-known title.
Duchess Kate's got her title because of Prince Edward...?
Originally, Queen Elizabeth II wanted to award the Duchy of Cambridge to another member of the Royal Family. According to reports, the Queen's youngest son Prince Edward was to become a Duke. But he preferred the title of Earl.
At his own request, he became an Earl instead of a Duke. His wife Sophie also became a Countess and not a Duchess, and Cambridge went to William and Kate.
Prince Edward, then, would have been the Duke of Cambridge, but he saw the film Shakespeare in Love and took a liking to a character named the Earl of Wessex.
"He liked the sound of it and asked the Queen if he could have that instead," a courtier revealed to The Telegraph in 2010.
The actor Colin Firth, who played the Earl of Wessex in the 1998 film, made a big impression on Prince Edward, who by the way almost became king of another land. So, in a roundabout sort of way, Kate can thank Firth for her royal title today.
William and Edward aren't the only royals to have received a duchy from the Queen. After her marriage to Prince Charles, Camilla Parker Bowles became Duchess of Cornwall and Duchess of Rothesay.