"I was in a hotel room on my own, I was sobbing my heart out, I downed half a bottle of champagne from the mini-bar in one and went home with mascara all over my face," Rowling, 41, said in a BBC interview.

The final novel in the seven-book series, "Harry Potter and the Deathly Hallows," will be published on Saturday — many bookstores will start selling it just after midnight tonight.

The novels have all been No. 1 best- sellers, spawning movies, audio books and computer games.

Commenting on speculation that the final word of the book is "Scar," Rowling said, "Scar? It was so for ages, and now it's not. Scar is quite near the end, but it's not the last word."

Harry's friend Hermione Granger is based on Rowling as a child. "I was quite swotty as a child," but Harry is a totally imaginary character, she said. Ron Weasley, another of Harry's friends, is "a lot like my oldest friend Sean," she said.

Rowling said last year that two characters die in the final book, leading many people to speculate that she may have decided to kill off the central character.

Rowling will mark the release of the final novel with a midnight signing session at London's Natural History Museum on Saturday. Rowling will also undertake a U.S. reading tour for children in Los Angeles, New York and New Orleans in October.

The books about the young wizard's adventures at Hogwarts School of Witchcraft and Wizardry have sold more than 300 million copies, earning Rowling a 545 million-pound ($1.01 billion) fortune, according to the U.K.'s Sunday Times newspaper. That makes her the 13th richest woman in Britain, eight places ahead of Queen Elizabeth II.

The first book in the series, "Harry Potter and the Philosopher's Stone," called "Harry Potter and the Sorcerer's Stone" in the U.S., was published in 1997.

The books have been translated into 63 languages, including Farsi and Chinese, Rowling's agent, the London-based Christopher Little Literary Agency, said in October 2005. The final novel is widely tipped to be the fastest-selling book of all time. The books are published by Bloomsbury Publishing Plc in the U.K. and Scholastic Corp. in the U.S

Rowling, who studied French at Exeter University in southwest England, said she was inspired to write the first book after the breakdown of her first marriage and the death of her mother, aged 45, from multiple sclerosis in 1990. Rowling wrote much of the first novel in cafes, while her young daughter slept in a stroller.