The Duke of Edinburgh shared a close bond with his eight grandchildren, but his kindness also extended to his in-laws, including the Duchess of Cambridge. The pair appeared to have a sweet relationship, with Prince Philip always making Kate laugh in public.
Before the Duke retired from public duties, aged 96, in August 2017, he was a regular fixture by the Queen's side at her engagements and formal events, such as Trooping the Colour.
Prince Philip was among the royals to welcome Kate to the fold upon her marriage to Prince William in 2011.
In the Duke of Cambridge's touching tribute to his late grandfather following Prince Philip's passing on 9 April 2021, William said: "I feel lucky to have not just had his example to guide me, but his enduring presence well into my own adult life – both through good times and the hardest days.
"I will always be grateful that my wife had so many years to get to know my grandfather and for the kindness he showed her."
Take a look back at Prince Philip and Kate's sweetest moments together…
READ: 14 heartwarming photos of Prince Philip as a doting grandfather
The Duke and Duchess of Cambridge looked pleased to see the Duke of Edinburgh as they left St George's Chapel in Windsor after Princess Eugenie and Jack Brooksbank's wedding. Prince Philip attended all of his adult grandchildren's nuptials, including Princess Beatrice's marriage to Edoardo Mapelli Mozzi in Windsor in July 2020
WATCH: Prince Philip and Kate's best moments together
Kate and Philip looked deep in conversation as they walked to church with William in Sandringham, Norfolk in January 2018. The Duchess was pregnant with Prince Louis at the time.
MORE: Kate Middleton's grandfather crossed paths with Prince Philip in the sixties - see photo
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The 2017 Trooping the Colour was the last time the Duke appeared on the balcony during the parade to mark the Queen's official birthday. William and Kate were joined by their eldest children, Prince George and Princess Charlotte, and at one point, Prince Philip made the Duchess burst into giggles.
MORE: Prince William shares adorable unseen photo of Prince George with great-grandfather Prince Philip
The pair sat next to one another at the patron's lunch to celebrate the Queen's 90th birthday in 2016 and it looked like they had so much fun together!
The Duchess beamed at the Duke as he turned to speak with her at the 2015 Trooping the Colour. It was one of Kate's first post-baby appearances after the birth of Princess Charlotte.
MORE: Princess Beatrice becomes emotional talking about her 'fabulous' grandfather - see unearthed video
The Duke of Edinburgh had a close relationship with Princes William and Harry, but it's clear that he also adored his granddaughter-in-law Kate. The foursome were pictured together at Trooping the Colour in 2014.
MORE: Prince Philip's sweetest family pictures with his children and grandchildren
The Duchess made her second appearance at Trooping the Colour in 2012, standing next to the Duke.
MORE: Prince Philip obituary: The Duke's incredible life from childhood to duty
Kate travelled to Leicester with the Queen and the Duke of Edinburgh on the royal train in 2012 and she seemed truly at ease with her in-laws.
The trio were given a whistle-stop tour of the city together, with Kate telling one well-wisher that while she was missing William (who was posted to the Falkland Islands at the time), she said: "I'm being well looked after."
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