After she was asked on Twitter to give a hint as to what the book would be called, Rowling said if someone correctly guessed she would confirm it.
She then hinted the title was two words made up of _ _ _ H _ _ / _ H _ _ _.
After many suggestions including Eighty Shoes, Mashed Chips, Mayhem Sheep and Mighty Thumb, someone correctly guessed Lethal White.
"Well, that was fun," Rowling tweeted, before promising the fan a signed copy of the book, "when I finally finish it".
