Three months before the release of the book, publishers Bloomsbury have given eager fans another clue about what will happen next to Harry.
It shows a phoenix, emerging from flames. And is the first cover not to feature Harry himself.
The contents of the book are so secret that even the artist, illustrator Jason Cockcroft, wasn't allowed to read it before drawing the cover.
Instead J K Rowling and her editor at Bloomsbury, Emma Matthewson, came up with the idea and then told the artist the kind of image they wanted them to create.
The adult cover, designed by Bloomsbury's Design director William Webb, is from a photograph by Michael Wildsmith and again shows a phoenix.
It is drawn in tones of midnight blue, indigo and flame blue and was illustrated by Mary GrandPre.
The book will be in the shops on 21 June.