London, July 23 : British writer JK Rowling revealed that she regrets not having told her mother, Anne, about the Harry Potter book she was writing.
Rowling had started writing the book just six months before her mother died of multiple sclerosis (MS) at the age of 45.
"I started writing Harry six months before she died. That's obviously a real regret, because I never told her I was even writing it," Daily Telegraph quoted her as saying in an interview for a BBC Scotland documentary.
"She knew I wanted to write - I'm not sure how seriously she took it. She never knew anything about Harry Potter at all," she said.
The series of books has gone on to sell 375 million copies worldwide and spawn five blockbuster films, with the sixth installment, Harry Potter and the Half-Blood Prince, due out in November this year.
Rowling, patron of the Multiple Sclerosis Society Scotland, also voiced frustration at the level of funding available for research into the debilitating disease.
Rowling further spoke of her pain at witnessing the gradual decline of her mother, whom she had perceived as "invulnerable", prior to her death in 1990.
"She had me very young. She had me when she was 20, so I was 25 when she died," the 42-year-old told the documentary.
"When I left home, she was walking unaided. By the time I graduated, she was in a wheelchair and in the house she needed a walking frame. It was awful to watch," she added.
Rowling, who contributed to the cost of a new MS research centre in Edinburgh, has labelled MS the "Cinderella of illness" because it is under-funded and ignored.