Kate Middleton has a three-inch scar running down the left temple of her head. You may or may not have noticed (it's not glaringly obvious), but when the Duchess of Cambridge made her first public outing, there were several rumours as to what it was caused by. Some believed it was from having had hair extensions in the past, while others thought it related to an injury on the hockey field (she often played as a child, and is still a big fan), but in case you missed the story at the time, the real reason is neither of these.
SEE: Kate Middleton and Prince William's homes: inside photos taken by the Duchess
WATCH: Kate Middleton returns to work with moving visit
Back in 2011, a spokesperson for Kensington Palace told E! News: "The scar is related to a childhood operation." No further details were given, but whatever the cause of the operation, Duchess Kate is as healthy as ever so it doesn't seem to be regarding an ongoing issue.
MORE: Inside Kate Middleton's childhood: Brownies, boarding school, growing up in Jordan and more
Kate Middleton's scar
As for the previous rumours, it seems unlikely that Kate would have had extensions - she has some of the glossiest, thickest locks we've ever seen, after all, and we're not quite sure how extensions would leave such a significant mark.
Hockey wise, Kate was in the team at both St Andrew's School and Marlborough College - her primary and secondary schools before heading off to study art history at St Andrew's University in Scotland, where she met Prince William in 2001 - and the sport does come with a risk of being hit by a stick that could have lead to an operation, but again, this is just speculation.
MORE: 7 things we learnt from Kate Middleton's revealing motherhood podcast with Giovanna Fletcher
Kate Middleton (bottom row, left) was in the hockey team at school
For now, Duchess Kate is happy and healthy. She's a mother to her three children with the Duke of Cambridge: Prince George, Princess Charlotte and Prince Louis, and the family are all well.
Kate Middleton went to secondary shool at Marlborough College
While Kate attended St Andrew's primary school, the Duke and Duchess of Cambridge's eldest children Prince George and Princess Charlotte are now attending Thomas's School in Battersea, and have recently returned post-summer holidays.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.