Kate Middleton's grandfather was photographed with Prince Philip nearly 50 years before she married into the royal family

• Kate Middleton's grandfather Peter was a co-pilot for Prince Philip's tour of South America in 1962.
• Captain Peter Middleton was photographed with Prince Philip when he disembarked at Heathrow Airport.
• Prince Philip died at the age of 99 on Friday.

Prince William and Kate Middleton met as students at St. Andrews University in Scotland, but her royal connection goes back even further.

Middleton's paternal grandfather, Peter Middleton, was a captain in the Royal Air Force and served as co-pilot during Prince Philip's two-month tour of South America in 1962, according to his 2010 obituary in The Times of London.

The two were photographed together when Prince Philip returned from the tour and disembarked at Heathrow Airport. In the photo, which resurfaced following Prince Philip's death on Friday, Middleton is the man furthest to the left, in uniform.

According to the obituary, Buckingham Palace sent Middleton a thank-you letter and a pair of gold cuff links after the tour.

Decades later, Middleton met his granddaughter's boyfriend, Prince William, at his 90th birthday party. He died two weeks before she and Prince William publicly announced their engagement in November 2010.

Prince Philip died on Friday at the age of 99. Prince William wrote in a statement published on the royal family's website that he "will always be grateful that my wife had so many years to get to know my grandfather and for the kindness he showed her."

"My grandfather was an extraordinary man and part of an extraordinary generation," the statement continued. "Catherine and I will continue to do what he would have wanted and will support The Queen in the years ahead. I will miss my Grandpa, but I know he would want us to get on with the job."