When the 37-year-old Prince was thirteen, he was hit in the head with a golf club.
'I call it [my Harry Potter scar] because it glows sometimes and some people notice it-other times they don't notice it at all,' William said in a 2009 interview.
'I got hit by a golf club when I was playing golf with a friend of mine. We were on a putting green and the next thing you know there was a seven-iron and it came out of nowhere and it hit me in the head.'
While Kate has never directly mentioned her scar in public, William regularly makes fun of his.