By Sky News SkyNews - 1 hour 55 minutes agoIt's the news all Harry Potter fans will have been hoping for - a new work about the boy wizard by JK Rowling. The author has penned a prequel to the bestselling seven-book series describing what happened to Harry before he went to Hogwarts. The fact that the new work - written for a charity auction - is just 800 words long is unlikely to dampen fans' enthusiasm for finding out what is in it. The new piece is one of 13 story outlines written by famous writers for a charity auction to be held by Waterstones on June 10. Others taking part include new James Bond writer Sebastian Faulks and Nobel laureate Doris Lessing. The money raised by the What's Your Story event will go to charities English Pen and Dyslexia Action. The writers could submit anything from a doodle and collage to a fresh story. So organisers were amazed when Rowling handed over a prequel to the Potter series, which has sold more than 375 million books worldwide. Rowling, who has earned a £560m fortune from the stories, is determined the latest instalment will not be developed further. She says at the end of the story, written on both sides of an A5 storycard: "From the prequel I am not working on - but that was fun!" The author has said that if she did write another Potter tale, it would not be for another 10 years. Philip Errington, a specialist at Sotheby's, which will run the auction, said the 13 storycards would be sold without reserve prices. He said: "Given the enormous interest we have seen in recent times for autograph work by JK Rowling, the prospects for her storycard are good to say the least. "There is just no telling how high the bidding might go." Waterstone's chief executive Gerry Johnson said: "What's Your Story just gets more and more exciting - all these brilliant works by amazing writers and illustrators, every one a small masterpiece. "We never dreamed that JK Rowling would donate something so precious, and we're incredibly grateful." Other authors who have donated outline works are Lisa Appignanesi, Margaret Atwood, Lauren Child, Richard Ford, Neil Gaiman, Nick Hornby, Michael Rosen, Axel Scheffler, Tom Stoppard and Irvine Welsh.