Kate Middleton had ANOTHER boyfriend when she met Prince William

THEY might be married with three adorable children now, but once upon a time Kate Middleton and Prince William were just friends.

And while the pair went on to have their ups and downs before finally tying the knot in 2011, one royal commentator has revealed that when the pair first met Kate was already in a relationship.

Speaking on the latest episode of 9Honey's The Windsors podcast, royal expert Victoria Arbiter revealed Kate was dating a man named Rupert Finch at the University of St Andrews - where she and Wills met.

"Kate actually had another boyfriend when she first got to St Andrews, Rupert Finch, who by all accounts was a nice man," said Arbiter.

"Rupert was ahead of Kate in terms of school, he left university in 2002.

"Prince William, he kind of expressed a bit of interest but I think Kate was still playing hard to get. She wasn't terribly sure if she was interested."

Kate's relationship with lawyer Rupert was only short term and it seems there were no hard feelings when the pair parted ways.

He and his then-girlfriend Lady Natasha Rufus Isaacs were invited to the Royal Wedding in 2011 and Kate and Wills were both at Rupert and Natasha's nuptials in 2013.

According to reports, it wasn't until Kate wore a risqué outfit at a student fashion show that she really caught Prince William's eye.

After seeing his now-wife in a see-through mesh dress William is reported to have said: "Wow, Kate's hot!"

According to royal expert, Katie Nicholl: "[William] suddenly noticed that this rather cute and charming girl who he’d gotten to know over lectures and breakfast was actually a real hotty.”

In Katie's book, The Making of a Royal Romance, a pal is quoted saying: “It was clear to us that William was smitten with Kate, he actually told her she was a knockout that night, which caused her to blush.

“She played it very cool and at one point when William seemed to lean in to kiss her, she pulled away.

“She didn’t want to give off the wrong impression or make it too easy for Will.”

The pair dated for four years before briefly breaking up in 2007.

During their engagement interview in 2010, William said: "At university, we were sort of both finding ourselves as such and being different characters and stuff, it was very much trying to find our own way and we were growing up.

"It was just sort of a bit of space and a bit of things like that, and it worked out for the better."