A young girl, hospitalized with anorexia, was disappointed that she would miss the book launch. However, she was released that day for a few hours and got a book signed by J.K.

J.K. Rowling told her that if she beat anorexia, she could audition for the role of Luna Lovegood.

She did, and she got the part.

(I've heard that this was false? Can anyone confirm this 100%)