Kate Middleton first spotted her future husband when she was just nine years old.

One of the world’s most high-profile fairytale romances began decades earlier, with a chance meeting.

It’s been well-documented that Prince William and Kate Middleton first met in 2001, when they were students at St. Andrews University. 

But, according to royal expert and biographer Katie Nicholl, the pair crossed paths in their elementary school days, when their schools, Ludgrove Prep and St. Andrews Prep, played each other in sports.

Listen to this episode of Lowbrow where Holly Wainwright breaks down the break-ups and make-ups of Prince William and Kate Middleton. Post continues after audio. 

In her book Kate: The Future Queen, Nicholl writes, "Although [Kate] wasn’t especially interested in boys, the arrival of one particular young man had caught her attention.

"Nearby Ludgrove Prep school would often play matches against St. Andrew’s Prep, and there was much excitement when Prince William, a left back on Ludgrove’s Colts team, came to St. Andrew’s to play a hockey match when he was nine years old.

"William, like Kate, loved sports and was one of the best hockey and rugby players in his year. Of course, the arrival of the prince generated a flurry of excitement."

Kate was also just nine years old at the time.

Nicholl added in her book that Kate’s former teacher Denise Allford said, "I remember when William came to play hockey. The boys wanted to know why so many cars had stopped on the way in because it was unusual. It was William’s protection officers and bodyguard."

It was then that Kate got her first glimpse at the future King of England before they would officially meet in 2001. She said in their first interview together in 2010 that she "went bright red" upon meeting him and "scuttled off, feeling very shy." 

Eventually though, the pair became good friends - although; he didn't attend much of the school's initial events.

"William wasn't there for quite a bit of the time initially, he wasn't there from Freshers' Week, so it did take a bit of time for us to get to know each other, but we did become very close friends from quite early on," the royal said. 

Prince William and Kate at their graduation ceremony, 2005. Image: Getty.

The royal pair weren't confirmed together until after a fashion show where Kate wore a sheer skirt as a dress over a bikini while Prince William sat in the audience. 

The documentary The Day Will and Kate Got Married broke down what the royal felt and revealed that moment changed their relationship for good.

"A switch had been flicked, he suddenly saw her in a different light, and I really believe that was the turning point in their relationship," royal commentator Katie Nicholl said.

William admitted things changed around then for him too.

"We were friends for over a year first and it just sort of blossomed from then on," William told The Telegraph in 2010. "We just spent more time with each other and had a good giggle [...] and realized we shared the same interests."

By the time they graduated in 2005, the pair had already lived together with other friends and were publicly dating.

The media became obsessed with Kate and even more so in 2007 when reports surfaced that they had broken up. 

"He broke up with Kate because he's met someone else who's turned his head," an anonymous source told The Observer at the time. "She's from a decent background but is very naughty and he finds her much more exciting."

But by the summer of 2007, Will and Kate rekindled - and even addressed their brief breakup as something that was necessary.

Prince William and Kate. Image: Getty.

"We were both very young... and we were both finding ourselves," the royal heir said. "It was very much trying to find our own way and we were growing up."

"I, at the time, wasn't very happy about it, but actually it made me a stronger person," Kate added - possibly insinuating the split was not mutual. "You find out things about yourself that maybe you hadn't realized. I think you can get quite consumed by a relationship when you're younger."

In October 2010, Will proposed to Kate and they were married in 2011. 

They now have Prince George, nine, Princess Charlotte, seven, and four-year-old Prince Louis, together.