J.K. Rowling said she was sad, but relieved, to have completed the final "Harry Potter" book as she greeted fans at the European premiere of the latest movie in the young wizard saga.

Hundreds of fans — dozens of whom had camped overnight to secure a spot in front of a London cinema — waved flags, placards and scarves as Rowling and the film's stars arrived at London's Leicester Square.

Rowling's "Harry Potter and the Deathly Hallows," the seventh and final volume in the series, will be published July 21.

"Finishing it was very, very emotional. It was a combination of relief and sadness really," she said.

Fans pleaded for clues, seeking to learn the answer to the most hotly anticipated plot twist: Will Harry die?

Rowling said details are a secret from even her own family.

"I'll want to know what the people in my house think of it," she said.

Leicester Square was draped in green and gold for the premiere of "Harry Potter and the Order of the Phoenix" to imitate the movie's Ministry of Magic.

Fan Janice Brophy, 20, said she had camped in the square since early Tuesday to be sure of a spot close to the theater.

"To be here, in the inner sanctum of the Ministry of Magic is amazing," Brophy said. "I'm such a big fan."

Daniel Radcliffe, Rupert Grint and Emma Watson were among the stars who attended the event. They have starred in all five "Harry Potter" movies.

"We're a big gang," said Watson. "We call it the Harry Potter family."

Radcliffe, who stars as Potter, said the newest film was darker than the previous four, which presented a new acting challenge.

"They're more challenging but that's what makes them more exciting for me as an actor," Radcliffe said. "That's a lot more fun to do than just the action side of things."

"Harry Potter and the Order of the Phoenix" opens in the U.S. on July 11 and in Britain the following day.