More than one million copies have been pre-ordered

The author will read from Harry Potter and the Deathly Hallows at the Natural History Museum at midnight on 21 July.

She will then meet 1,700 fans and sign their copies of the book in a session that is expected to last until dawn.

The fans will be chosen in a ballot. Those wanting to be there must apply by 11 June at www.bloomsbury.com/jkrevent.

All 1,700 fans will get a free copy of The Deathly Hallows and have it signed by Rowling, while the first 500 randomly selected winners will also be invited to attend the reading.

"Ten years after publication of Harry Potter and the Philosopher's Stone, the launch of this, the final book in the series, returns to where it all began: with a book, the author and her readers," publishers Bloomsbury said in a statement.

Rowling has said two characters die in the final book, but has not revealed if Harry is one of them.

The Potter books have sold 325 million copies worldwide, have been translated into 64 languages and spawned five films.

The fifth film, Harry Potter and the Order of the Phoenix, will be in cinemas next month.