Washington, Sept 18: A set of Harry Potter books signed by author JK Rowling is set to go under the hammer for charity next Monday on online auction site eBay.

Books Abroad, which is marking its 25th anniversary with a fundraising ball, provides these books to schoolchildren across the world, and estimates that the autographed series will raise at least 20,000 pounds.

"No other complete set of signed Harry Potter books is available in the world at the moment," Contactmusic quoted the charity, as saying.

Claire Newman, development officer at the charity added: "Although she cannot attend our 25th anniversary in person, she was very keen to support us. We are very grateful to her for this generous contribution to our fundraising efforts."

The books were brought in by Barbara Murray, Rowling’s mother-in-law, and a volunteer for Books Abroad.

Murray had asked her daughter-in-law for to sign one copy of the book to be auctioned, as a part of the charity’s 25th anniversary celebrations.

Instead, the author sent a complete set of seven, all autographed, reports Times Online. (With Inputs from ANI)