Daphne Dunne, the self-proclaimed “biggest fan” of Prince Harry, has died aged 99.

Ms Dunne, a former servicewoman, died of pneumonia on Monday.

On three occasions, Ms Dunne managed to capture the attention of Prince Harry when the Royal visited Australia, most notably in 2018 when the Duke of Sussex rushed over to her at the Sydney Opera House.

Prince Harry saw her in the crowd at the meet-and-greet, embracing Ms Dunne and introducing her to his new wife, Meghan Markle the Duchess of Sussex, during a lengthy chat.

The Opera House proved to be a lucky spot for Ms Dunne, as it was also where she first caught Prince Harry’s attention in 2015 by wearing her husband’s Victoria Cross.

Prince Harry introduced Daphne Dunn to his new wife Meghan Markle on their third meeting in Sydney. Photo: AAP

“It is with the saddest of hearts that I would like to share the news that our most beloved mum and nanna, Daphne Dunne, passed away peacefully yesterday morning,” Ms Dunne’s family posted on Instagram.

“She was a truly special lady who will be greatly missed by so many.

“She spent a large part of her life representing the women of the Australian Army and her two husbands Lt. Albert Crowne VC MM and John Patrick Dunne, ensuring that their service to Australia was never forgotten.

“It is fitting that Daphne passed away on the first of April as it is a month of renewal, remembrance and reunification with her loved ones that passed before her.

“We love you mum/nanna/Daphne, always and forever.”

Daphne Dunne was a former servicewoman who received a birthday letter from Prince Harry just days before she died. Photo: AAP

The news came just days after the Duke of Sussex penned a letter to Ms Dunne, congratulating her on her 99th birthday.

“Dear Daphne, my wife and I send our warmest wishes to you on the occasion of your 99th birthday on Friday,” Prince Harry wrote.

“We hope you have a wonderful celebration surrounded by family and friends and that you’ve managed to escape hospital!

“Congratulations on reaching this important and impressive milestone before your centenary year next year.”

The letter was signed “Harry and Meghan”.

–ABC