The Duke of Sussex is said to be 'deeply saddened' by the loss of Daphne, whom he met for the first time in Australia back in 2015.
Two years later, Harry returned Down Under with Meghan Markle and introduced his wife to his most loyal fan.
“I was looking for you earlier and hoped you’d be here. It’s so good to see you again,” Harry told Daphne at the time before embracing her.
But it was Meghan who really impressed the war widow who gave the former actress her tick of approval.
"She's just what the prince needs," A caption reads on a photo of the royal lovebirds which was shared on an Instagram account dedicated to Daphne where she's referred to as "Prince Harry's Australian Grandma."
So moved by his numerous encounters with Daphne that it is understood that Harry plans to write privately to the family in Sydney to express his condolences.
It comes just days after Daphne, who had been in hospital with pneumonia for two months, celebrated her 99th birthday and received a card from the Duke and Duchess of Sussex, much to her delight.
"Today I celebrated my 99th birthday. I received a lovely message from Prince Harry and Meghan which really made my day," another post read on Instagram.
The couple’s thoughts are said to be with Mrs Dunne’s family and friends at this difficult time.
Watch Prince Harry's heart-felt birthday message to 99-year-old Aussie fan Daphne just a week before she passed away