Kate Middleton was left heartbroken by her first love at the tender age of 16, long before she met Prince William.
A new biography of the Duchess, entitled Kate: The Future Queen, reveals that she dated Harry Blakelock while she attended Wiltshire boarding school Marlborough College.
When they split, Kate was so devastated that she refused to date anyone else for three years.
The book's author, Katie Nicholl, told Now Magazine: "Harry Blakelock was Kate's first real love. He was widely acknowledged as the best-looking boy at the school.
"Harry was in the year above Kate and was very handsome, charming, good at sports and popular. He was a real catch.
"Kate described him as her "first proper love", so it knocked her when he dumped her to go travelling."
Nicholl, royal editor for the Mail on Sunday, also spoke about Blakelock on American talk show Katie, hosted by ABC News correspondent Katie Couric.
"He [Blakelock] was the hottest boy at Marlborough school," Nicholl told Couric, according to E! Online. "He was in the year above Kate, a great cricketer, a very talented sportsman, and when Kate came back for her first year of sixth form, she'd emerged into this beauty.
"She caught the eye of the best-looking boy at school and they actually had a romance for nearly a year and he was her first love, and he broke her heart."
According to Nicholl, Kate Middleton and Prince William knew each other before they enrolled at St. Andrews University in 2001.
"This was really fascinating for me. I was speaking to some of her friends at Marlborough School, which was where she went before St. Andrews, and they said "uh uh, she didn't meet him at St. Andrews. She met him before she got there...through some of her friends. They knew Prince William and Prince Harry,'" she said.