NEW YORK (Reuters) - Fans of British author E.L. James' Fifty Shades Of Grey erotic trilogy clamoured on Thursday to get the first copies of her new book Grey, a version of the first novel told through the eyes of her famous male character.

At Barnes & Noble bookstore in Manhattan, where James was doing a book signing on Thursday, the line stretched around the block.

"Grey was the highest Kindle pre-order book of the year on Amazon.com when it was released as an ebook at midnight and is expected to be an instant bestseller.

Publisher Vintage Books, a division of Knopf Doubleday Publishing Group, supplied a million copies of the novel to bookstores.

Fifty Shades Of Grey and its two sequels Fifty Shades Darker and Fifty Shades Freed sold more than 125 million copies worldwide and was published in 52 languages.

James, who dedicated the novel to fans who asked for a book told from the perspective of billionaire Christian Grey, said the book was not difficult to write.

"I thought it would be hard but once I found his voice it was actually quite easy. Like any man, he is not observant, at all," she said in an interview on the Today early morning news show.

In the novel, James gets into the mind of the handsome, troubled 27-year-old business tycoon with a penchant for kinky sex, who introduces naive college student Anastasia Steele to sadomasochism and bondage.

The novels have been dubbed "mommy porn" for the fantasy they provide for their millions of fans.

Early reviews of Grey say it is the raunchiest book of the series and holds nothing back in revealing Grey's deepest desires and secrets.

"While action-hungry fans will be thrilled by the more graphic sex scenes, romance lovers will finally get the answers they've been craving," said Britain's Daily Mirror newspaper.

The Guardian newspaper chimed in saying, "This book is far more realistic and creepy beyond belief."

The first book of the trilogy was turned into an R-rated film by Comcast Corp-owned Universal Pictures starring Dakota Johnson and Jamie Dornan, grossing more than US$500 million (S$666 million) at the global box office since its February release.

Several countries, including India, Malaysia, Indonesia and Kenya, banned the film from their theatres because of its erotic content.

Critics said the movie blurred the lines between healthy and harmful sex.

Film adaptations of the second and third books are planned.