But in the latest diary entry on her official Web site (www.jkrowling.com), Rowling gives no hard clues as to what will happen at the end of the upcoming book, amid speculation that some of the characters, possibly Harry himself, will die.

"For years now, people have asked me whether I ever dream that I am 'in' Harry's world," Rowling continued in her diary. "The answer was 'no' until a few nights ago when I had an epic dream in which I was, simultaneously, Harry and the narrator."

Rowling described how, as Harry, she was searching for the Horcrux (a magical object), while as the narrator in the dream she knew where it was all along.

She saw waiters and waitresses from the cafe where she has been writing the book walking on stilts making them "at least 15 feet high. Perhaps I should cut back on the caffeine".

There is no firm date set for the completion of the final Harry Potter book, although it is expected to hit the shelves some time in 2007.

"I'm now writing scenes that have been planned, in some cases, for a dozen years or even more," she wrote in the diary entry dated December 19.

"I am alternately elated and overwrought. I both want, and don't want, to finish this book (don't worry, I will)."

The book series has sold an estimated 300 million copies worldwide, making Rowling one of the most successful authors of all time. A film franchise has also taken the box office by storm, earning billions of dollars from four films made so far.

Rowling, 41, said she had seen a 20-minute clip from "Harry Potter and the Order of the Phoenix", the fifth film based on her series due out next year, which she called "fantastic".

Earlier this year Rowling said at least two characters would die in the final book, but she did not name them.