Prince William and Catherine Middleton appear to be the perfect royal couple.

They always seem to know exactly what to do and how to behave in the public eye.

However, they haven’t always followed the rules of the royal family.

Prince Harry and Meghan Markle hold hands behind Prince William and Kate Middleton.

So, why do William and Kate remain so formal in public?

“Their more tactile PDAs include back-touches or placing an arm around each other’s waists.”

Prince William and Kate Middleton at an event.