A prequel to the Harry Potter series of novels is to be auctioned for charity next month.
Jk Rowling has written an 800-word outline of a preface to the stories of the boy wizard but will not publish the text, instead adding it to a tempting literary lot at a June 10th auction.
The millionairess is one of 13 authors to have written storycards for Waterstone's, with all 13 cards to be auctioned at Sotheby's without a reserve price, with the proceeds going to the English PEN and Dyslexia Action charities.
A printed postcard book - featuring the works by Rowling, Tom Stoppard, Irvine Welsh and Nobel laureate Doris Lessing among others - will go on sale in August.
Though the details of Rowling's contribution are not yet known, her outline is said to end with the handwritten dedication reading: "From the prequel I am not working on - but that was fun!"
Gerry Johnson, managing director of Waterstone's, commented: "What's Your Story just gets more and more exciting - all these brilliant works by amazing writers and illustrators, every one a small masterpiece, and now this - the prequel to Harry Potter.
"We never dreamed that JK Rowling would donate something so precious, and we're incredibly grateful," he added.
Sotheby's specialist Philip Errington, said that in light of the £1.95 million paid for her handwritten book of stories The Tales of Beedle the Bard in December, "there is just no telling how high the bidding might go" at the new auction.
Other authors involved include Margaret Attwood, Lauren Child, Neil Gaiman, Nick Hornby, Michael Rosen and Sebastian Faulks.