In a touching display, the last time the mother-of-three wore the Japanese Pearl choker was during Queen Elizabeth and Prince Philip's 70th wedding anniversary dinner four years ago.
Whilst the couple's three children Prince George, seven, Princess Charlotte, five, and Prince Louis, two, were absent from the event, Duchess Catherine was there to lend her support to husband, Prince William.
Due to COVID restrictions and the Duke of Edinburgh's personal wishes, the funeral was a small affair, attended by only 30 close relatives and friends.
Prince Philip's passing came just days before Will and Kate were set to celebrate their milestone 10th wedding anniversary on April 29.
Ahead of the funeral, reports suggested that the Duchess of Cambridge would play peacemaker between her husband and his younger brother, Prince Harry as they make their anticipated reunion.
"Being so close to her own siblings, Pippa and James, and having witnessed firsthand the special bond between William and Harry, she has found the whole situation difficult and upsetting," a source told the Telegraph UK.
The royal brothers' relationship has been frosty over the last few months ever since Harry and his wife Meghan Markle's explosive tell-all interview with Oprah Winfrey.
In the interview, one bombshell dropped was when Meghan mentioned that the story of her making Kate cry ahead of the 2018 royal wedding was false and that it was the Duchess of Cambridge who brought Meghan to tears.
Prince William released a poignant statement in the wake of his grandfather's passing that was accompanied by a previously unseen photo of the Duke of Edinburgh and a young Prince George, taken by the Duchess of Cambridge herself.
"My grandfather’s century of life was defined by service – to his country and Commonwealth, to his wife and Queen, and to our family," Prince William wrote in the statement.
"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. I will never take for granted the special memories my children will always have of their great-grandpa coming to collect them in his carriage and seeing for themselves his infectious sense of adventure as well as his mischievous sense of humour!