Kate Middleton, the Duchess of Cambridge, has sent a heartfelt letter to a 9-year-old cancer patient in Royal Marsden Hospital, which she and Prince William visited in September.

Fabian Bate, who has been battling with leukemia, received a letter from Kate Middleton and posted it on his blog. The note was written on Oct. 13 on a simple letterhead that said St. James’s Palace and was signed “Catherine.”

“Despite the enormously demanding course of treatment you are undergoing, I was so touched by your strength of character, and delighted to hear the news that one of your big sisters will be able to donate bone marrow to you later this year,” Middleton wrote. ”I will keep my fingers crossed that your health goes from strength to strength over the months ahead.”

“This must be a troubling time for you, your parents and your sisters, but I know I left The Royal Marsden assured by how incredibly talented, kind and clever the team at the hospital are. Combined with your belief and positive energy, you couldn’t be in better hands.”

“Keep up the good work with the blog,” she encouraged Fabian, “and in the meantime I will keep you and your family in my thoughts and prayers.”

Fabian's father, Darrell Bate, 49, told People that the letter encouraged his family a lot. For us as a family it was a massive boost to know that we have someone at Kate's level sharing our journey, Darrell said. The thought that someone in her position would take that personal interest is a real hope-builder.

For the Fabian, who is suffering from the leukemia, It's a real morale booster and it was really quite personalized to him and he has something to cherish for years to come, Darrell said. This is something to talk about with our family and friends.

If [Kate] is going to take the trouble to follow our little family situation with everything else going on in the world, it makes Fabian feel special, Darrell added. It gives him a bit more fight to be honest.

Fabian Bate was diagnosed with leukemia in 2006. There will be a test this week to find out if he can as early as December receive a bone-marrow transplant from one of two sisters who've been found to be a perfect match.