The release date for the sixth Harry Potter movie, the Half-Blood Prince, originally set to enter cinemas in November, has been pushed back until July 2009. The eight-month change is expected to disappoint millions of Harry Potter fans around the world who have already been itching with anticipation for more than a year to watch the next big-screen instalment of the series. Warner Bros, the production company behind the franchise, said it had decided to make the change to bolster its release schedule for the lucrative summer moviegoing season - a period that can account for as much as 40 per cent of Hollywood's annual box office receipts. The film is the first of a two-part adaptation of Deathly Hallows, the seventh and last story from British author JK Rowling. The series has sold an estimated 400 million copies, and the books have been translated into more than 60 languages. Meanwhile, admirers of Potter star Daniel Radcliffe have been offered an incentive that could make the wait for the film that little bit more worthwhile. The actor, who appeared in the stage production of Equus - where he was fully nude for much of his performance - hinted that his wizard character may follow suit - or not as the case may be - and shed some clothes for the film.