In Sydney last October, Harry was able to introduce Dunne to Meghan Markle

One of Prince Harry‘s biggest admirers has died, according to multiple reports.

Daphne Dunne, the longstanding royal fan from Australia, died in her home on Monday, the BBC reported. She was 99.

Harry and wife Meghan Markle are planning to write to Dunne’s family, a royal source tells PEOPLE. The couple is “deeply saddened by the news and they are thinking of Daphne’s family at this time,” the source says.

Prince Harry and Daphne Dunne in 2018
| Credit: Chris Jackson/Getty

The parents-to-be will send a private letter of condolence and sympathy to the family of the war widow, who Harry, 34, has met regularly when he visits Australia. She was known for wearing her late husband’s military medals when she met the prince.

It was only last week that the Duke and Duchess of Sussex sent Dunne some special wishes on her 99th birthday.

On a letter topped with Harry and Meghan’s joint monogram, the message from the prince read: “Dear Daphne, My wife and I send our warmest wishes to you on the occasion of your 99th birthday on Friday. 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. Happy birthday, Daphne.”

Prince Harry, Meghan Markle and Daphne Dunne in 2018
| Credit: Samir Hussein / WireImage

Dunne met the royal twice before his latest visit to Sydney. They first crossed paths in 2015, when she memorably planted a kiss on Harry’s cheek.

Prince Harry Visits Sydney
Prince Harry and Daphne Dunne in 2015
| Credit: Dean Lewins - Pool/Getty

And in Sydney last October, Harry was able to introduce her to Meghan, 37, his new wife — who had only just revealed she was expecting the couple’s first child.

“Congratulations, I think that’s marvelous,” Dunne told the duchess of the baby news. “It’s just what Harry needs.”