Years before the Duke and Duchess of Cambridge were even born, both of their grandfathers surprisingly crossed paths.
Kate's grandad, Captain Peter Middleton, was a pilot who flew alongside Prince Philip as a co-pilot during the late royal's two-month flying tour of South America in 1962.
WATCH: Prince Philip's best family moments
In a resurfaced picture, the Duke of Edinburgh - who passed away on Friday - could be seen disembarking a plane at Heathrow Airport, while Peter stood alongside the stairs of the aircraft, dressed in uniform.
Peter sadly died at the age of 90 just days before Prince William and Kate announced their engagement in 2010, while Prince Philip passed away just weeks before the royal couple were due to mark their tenth wedding anniversary.
Kate's paternal grandfather studied English at New College, Oxford and served as an RAF fighter pilot during the Second World War. Her grandmother, Valerie Glassborow, worked at the Second World War Government Code and Cypher School in Bletchley Park - along with her twin sister Mary.
Peter Middleton pictured standing next to the aircraft
Records show that her paternal grandmother - who died in 2006 at the age of 82 - worked as a Duty Officer. She married British military pilot Peter in 1946.
In May 2019, Kate paid a fascinating visit to Bletchley Park to meet young children taking on the role of codebreakers. The mother-of-three viewed a special D-Day exhibition to mark the 75th anniversary of the D-Day landings, and joined a group of youngsters in their codebreaking workshop. The boys and girls re-enacted what it was like in June 1944 to intercept and decipher German communications.
Kate opened up about her grandmother Valerie Glassborow, and Valerie's twin sister Mary, saying: "My granny and her sister worked here. It's very cool. When she was alive sadly she could never talk about it. She was so sworn to secrecy that she never felt able to tell us."
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