Kate Middleton smitten by Prince William after seeing him in a uniform

Prince William wearing a uniform in an old video appears to have left Kate Middleton completely smitten by him.

According to a lip reader, the Duchess of Cambridge was seen mouthing the word ‘sexy’ while eyeing her then-future husband’s RAF graduation at Sandhurst back in December 2006.

The clip making rounds online is four years prior to the couple’s wedding as she attended William’s big event with her parents Carole and Michael Middleton.

The lip reader has now revealed what the duchess said, something that is quite unlikely to be uttered out of the mouth of a royal family member.

As quoted by Mirror, the lip reader told said during a True Royalty TV appearance: "I love him in uniform, he's so, so sexy.”

That particular day was significant in the couple’s life as one royal expert claims that is when they realized they would end up getting married.

Speaking on Channel 5’s documentary, William & Kate: Too Good To Be True: “We hadn't expected Kate and her family to turn up, and myself and a number of photographers and journalists were all standing on a press stand together.”

"Suddenly out of the corner of her eye we saw Kate and her mother and father being ushered down to the front of the seating,” she said.

"I remember turning to the person next to me and saying that's it, it's a done deal. This woman is going to be our future Queen,” she added.

Victoria Arbiter, royal expert, also added: "Suddenly the engagement whispers were starting. There was intense pressure on William and Kate, and short of printing the tea towels, everyone had these two walking down the aisle imminently.”