Did you know that when they first met at St Andrews University in 2001, they had no idea that they would become royalty?
After around 10 years of dating, they finally tied the knot in 2011, in a grand ceremony that was watched by millions.
The couple now have three children together: George, Charlotte, and Louis. How cute!
But that's not all – they also get to keep their Cambridge titles, and will inherit the Cornwall titles from Charles and Camilla.
William is now first in line to the throne, with little George becoming second in line. That's a pretty big responsibility!
Grant Harrold, their butler, said they were "no different to any other couple that were beginning off, in love and spending time together".
In fact, Harrold felt "privileged and honored" to be around the couple, whom he described as "brilliant" and "great fun". Who wouldn't want to hang out with them?
Kate was forgotten during Prince William's birthday celebration! Believe it? Luckily, the butler treated her like a princess.