Will the magic wear off?

Warner Bros., the studio behind the “Harry Potter” blockbusters, could find itself in an awkward position when author J.K. Rowling lets the black cat out of the bag next month about the ultimate fate of her characters.

Ten days after the fifth installment, “Harry Potter and the Order of the Phoenix,” hits theaters July 11, the world will know what happens to the bespectacled boy wizard and the rest of his Hogwarts gang with the release of “Harry Potter and the Deathly Hallows,” Rowling’s seventh and final book in the series.

Last year Rowling revealed in interviews that she would kill off two characters, and that one character “got a reprieve,” never acknowledging whether Harry is among them. Potter fans have been rigorously debating on Web sites whether the British author will dare terminate the beloved star of what has become the biggest-selling series in literary history.

Warner doesn’t expect any spoilers to hurt box office sales of its upcoming film. Indeed, the flurry of publicity surrounding the release of a new movie and book could feed off each other.

But there are still two more “Harry Potter” sequels to go over the next three years. So could knowing how it all ends dissuade moviegoers from turning out to see them?

Warner President Alan Horn said he’s not worried.

“Whatever happens to Harry Potter, I would not anticipate it hurting the movie or future movies in any way,” he said.

Horn said that four months before the fourth film, “Harry Potter and the Goblet of Fire” was released in 2005, moviegoers had already learned that in Rowling’s sixth book that Albus Dumbledore — Headmaster of Hogwarts School of Witchcraft and Wizardry — had died.

“And, he was a beloved character,” said Horn.

Horn also noted that James Cameron’s 1997 “Titanic” was a blockbuster even though virtually everyone knows the luxury liner sank, killing most of its passengers. And, Horn said, fans of J.R.R. Tolkien’s “Lord of the Rings” knew the ending of the author’s trilogy, but still turned out in force for the films.

“Harry Potter” has been a global juggernaut for the studio. Worldwide, the first four movies have grossed $3.5 billion and sold 167 million DVD and VHS units.

Warner and parent Time Warner Inc. also amassed hundreds of millions more in profits from television, videogame and merchandising sales, such as a Lego Hogwarts Castle that retails at $89.99. Three weeks ago, Warner struck a major licensing deal with Universal Orlando Resort for a $200 million-plus Harry Potter theme park attraction in Florida that is expected to open in late 2009.

In the past, Rowling has offed key characters, including Hufflepuff Quidditch captain Cedric Diggory and Sirius Black from the once notable Wizard family. Many readers were upset about Dumbledore’s death scene on top of the Astronomy tower, with some devotees still insisting that he may have faked his own death and will return in the final book.