The little girl who charmed Prince William and Kate when they visited Calgary in the summer got her Christmas wish and is cancer free.

Diamond Marshall's brief meeting with the Duke and Duchess of Cambridge on a windy July day brought many people to tears.

Diamond was battling a rare form of adrenal cancer at the time but managed to get in a hug with Kate and give her flowers.

The touching moment was made possible by the Children's Wish Foundation.

Diamond had surgery on Monday and the family found out on Tuesday that the biopsies were cancer free.

Lyall Marshall, Diamond's father, said he believes that brief encounter with the royal couple helped his little girl battle the disease.

"That hug had a lot of meaning, we're very thankful for that meet and greet for her and the whole community rallying behind her," said Marshall. "From a father's point of view when you can say the whole world is rooting for you to get better, I mean that's a lot."

William and Kate were told by their private secretary about Diamond's miracle Christmas prognosis and in a statement said, "This is a wonderful piece of news, especially at this time of year and we will be thinking of Diamond in the coming year."

Diamond will spend Christmas in hospital recovering from surgery, but her dad says they're all okay with that as long as they're together.