J.k. Rowling said this quote
“ They think I'm a waste of space, actually, but I'm used to—I don't think you're a waste of space.If Harry had not seen Dudley's lips move, he might not have believed it. As it was, he stared at Dudley for several seconds before accepting that it must have been his cousin who had spoken; for one thing, Dudley had turned red. Harry was embarrassed and astonished himself. ”