Princess Grace Kelly had a grand total of 3 children who have all married multiple times and have had children in and out of wedlock... You can imagine how confusing it was choosing the next air to the Monégasque throne after all these children were born...

Grace Kelly: These Are Her Grandchildren 

Find out all about her grandchildren in the video above!

Prince William and Duchess Catherine in Bradford on Wednesday.

Test your knowledge!

When did Prince William and Kate Middleton get married?