The world's most popular children's author, J. K. Rowling, admitted yesterday that she's "terrified" of reading at the SkyDome tomorrow.

"I really enjoy doing readings, but I've never done it before in these numbers," the writer of the Harry Potter series said yesterday at a Toronto press conference.

"The most I've read for was 2,000 in Germany, with a translator," she said at the Royal York Hotel, where she later was given the keys to the city by Mayor Mel Lastman and spoke briefly at a $500-a-plate benefit luncheon.

She joked she agreed to do the SkyDome reading in a weak moment when she was in the middle of writing Harry Potter and the Goblet of Fire, the latest in the series, and just wanted to be left alone to write.

"The reading is a way to reach a lot of children. But I'm plainly not a rock star, not the Rolling Stones."

Organizers for the reading, part of the International Festival of Authors, will not comment on ticket sales, saying only the SkyDome has been configured to hold 36,000 spectators.

In person, Rowling (her friends call her Jo) is a slim, intense young woman dressed conservatively in black and gray, with longish blonde hair whose dark roots show. Her elegant hands sport a French manicure and she wears dangly diamond earrings and a diamond studded watch as her only ornaments.

She handles the media like a pro, ignoring the many cameras pointed in her direction. She answers questions succinctly, but it's clear she is more relaxed with children - many of them approached her starry-eyed at the luncheon afterwards - and likes their questions better since they never ask about fame or money or the Portuguese ex-husband.

She gets hundreds of queries from young readers by mail and in person: For example, what is a certain character's favourite colour or why does a stool described as having four legs in Book 1 have three in Book 4 of the seven-part series?

"Children ask the best questions. These (the characters in her books) are mutual friends of ours that I happen to know better," she says.

She says she writes for six to 10 hours a day, "if I have enough caffeine."

A single mother with a small daughter, who could not afford a computer to write with until the Scottish Arts Council gave her a grant, she is tired of the notion that hers is a Cinderella story.

"It doesn't feel that way when you're living it. We were very broke and now I'm grateful every day that I don't have to worry about money.

"But it was a lot of hard work. I was not sitting by the fireplace waiting to be discovered by the prince."

In the past three years, since the runaway success of her stories about the orphaned boy wizard, Harry Potter, and his escapades with his friends Ron and Hermione at the Hogwarts School Of Witchcraft and Wizardry, she has reportedly become the second-richest woman in the United Kingdom, after the Queen.

"Magic is a perennial theme in children's literature because children are so powerless," she explained.

She said she had not planned to write as long a book as her latest, Harry Potter And The Goblet Of Fire (635 pages). "I nearly had a heart attack when I first printed it out, but I needed that many words to tell the story."

She promised the next one, to be called Harry Potter and the Order Of The Phoenix, will be shorter, but would reveal nothing more about it.

Will there be life after Harry? "I'll definitely be writing post-Harry. It will be hard to let go of him. I'll be slightly bereaved. I may write something for adults or I'll continue to write for children. One thing for sure, I'll write. I've been writing since I was 6. But I know I'll never have a success like Harry again."

The luncheon that followed raised money for the Osborne Collection of the Toronto Library, a collection of historical children's books that Rowling visited for an hour on Saturday at the Lillian H. Smith branch on College St.

"She was wonderful, very appreciative," said Leslie McGrath, head of the collection. "We showed her her own books in special cases, and told her they would still be here in 200 years."

The Toronto-based collection houses more than 60,000 literary works, with some dating back to the 14th century.

Fittingly, since she lives in Edinburgh, Rowling was piped into the ballroom of the hotel by a bagpipe player.

Lastman, billed as "Toronto's chief Muggle," gave her the key to the city, saying she has a gift to inspire children to read.

"May Harry Potter live in the hearts and minds of the young and the young-at-heart," he said. He also gave her a pair of foam moose antlers.

Rowling spoke about her visit to the Osborne Collection and expressed the hope that "it will continue to flourish and expand."