A mother of young patient of cancer who was recently diagnosed has thanked JK Rowling author of Harry Potter series for helping her daughter through the treatment Chrissy Hart. And Hart’s letter was read aloud in the live performance by actress Ellie Bamber.

The letter has written “I write to you as a mother, a Mummy, of a beautiful little girl. I'm sure you hear people tell you all the time that your words, your imagination helped them, or their children, in some way. I want to share with you what you taught my daughter, who was recently diagnosed with cancer...You taught her that for every chemo she has to go through, there will be the opportunity to fly across a lake on a hippogriff.

For every time her heart seizes with fear of pain, there will be me chasing it away with a patronuscharm. Your words built a castle for her to move into when the prognosis got worse. Mrs Rowling, cancer threatened to take everything from my daughter, and your books turned out to be the fortress we so desperately needed to hide in.

But the most important lesson you have taught us both: cancer may take her away from me in just a few short weeks. I might not be able to spare her the pain. But for every child that is taken too early, people will come together, huddling close in a big group, wands held high to light the dark sky with the love they felt. You built Hogwarts as a home for her to return to. And for me. For that I shall remain forever gratefully yours...,"