When Kate Middleton and Prince William visited the Royal Marsden hospital in 2011, young cancer sufferer Fabian Bates stole their hearts, so much so that Kate continued to write to Fabian long after they said their goodbyes.
Now, the youngster tells HELLO! how William and Kate have helped towards his dramatic recovery from Leukaemia.
Fabian is full of energy as he recalls his inspirational chat with the royals: "When I met them, William told me to continue to be brave. I have followed his advice and it has helped me a lot as have the Duchess' letters to me."
When he met Kate almost two years ago, Fabian had lost his hair and was awaiting a life-saving bone marrow transplant. His 13-year-old sister Cassia-Rose has since donated her bone marrow and her brother has made a miraculous recovery.
Even as Fabian celebrates the first anniversary of his transplant with a party for his friends at his home near Hampton Court, his mother Lydia reveals that the royals still keep in touch for an update.
"They phone the hospital every four to six weeks to find out how all the children they visited are progressing," she tells HELLO!.
"And Fabian has received three letters from Kate's office since that visit, in which she talks about her absolute delight that he is in remission.
"He got a lovely letter back from Kate's office after drawing her a picture of Kensington Palace and another one when my husband let her know about how well Fabian was progressing.
"The fact they have kept up contact has helped lift not only Fabian's spirits but those of the whole family."
It's a little princess!