JK Rowling has revealed that she has written a secret manuscript which has yet to see the light of day.
But Harry Potter fans will be disappointed to learn that the work, a political "fairytale", will likely never be published - as it is scrawled onto a party dress.
The "book", which she penned two years ago for a fancy-dress birthday party, now hangs in her wardrobe alongside more conventional clothing.
"The theme of my 50th birthday, which I held at Halloween even though that's not really my birthday, was come as your own private nightmare," she told US broadcaster CNN.
"I went as a lost manuscript. And I wrote over a dress most of that book. So that book, I don't know whether it will ever be published, but it's actually hanging in a wardrobe currently."
The author revealed the existence of the unusual manuscript after being asked by CNN's Christiane Amanpour about plans to write a political book for children.
Rowling said the fairytale "wasn't political in a sort of party political sense" and hinted she may never publish it.
She was speaking to the broadcaster about Lumos, the charity she founded in 2005, which calls for an end to the institutionalisation of children.
The author said she felt compelled to do something after reading a newspaper article about children living in cages in a Czech orphanage.
"I'm flicking through the Sunday paper and I saw [a picture.] I see it in my memory. It was a very disturbing image of a very small boy screaming through chicken wire," she said.
"I stopped and I thought, if the story is as bad as the picture looks, then you have to do something about it. I was just appalled and horrified."
