Author J.K. Rowling listens to a question from the media during a press conference in this Tuesday, Aug 1, 2006, file photo taken in New York.[AP]

LONDON - " Harry Potter and the Deathly Hallows," the last of seven installments of the boy wizard's adventures, will be published July 21, author J.K. Rowling said Thursday.

Rowling announced the publication date on her Web site.

Bloomsbury, her British publisher, said it would publish a children's hardback edition, an adult hardback, a special gift edition and an audio book on the same day.

Scholastic Children's Books, the U.S. publisher, said it would offer a hardback edition at a suggested retail price of $34.99, a deluxe edition at $65.00 and a reinforced library edition at $39.99.

Bloomsbury noted that this year is the 10th anniversary of the publication of the first "Harry Potter" book in the phenomenally successful series.

The "Potter" books have sold 325 million copies worldwide and been translated into 64 languages, Bloomsbury said.

The last book, "Harry Potter and the Half-Blood Prince," sold 2,009,574 copies in Britain on the first day of its release, Bloomsbury said.

The Potter franchise is so important to the company's earnings that it announced the publication to the London Stock Exchange.

Bloomsbury shares were up 2.2 percent to $4.40 after the announcement.