The sales for E.L. James' bdsm novels are at 10 million and counting, making it among the fastest-selling series of all time, according to the Associated Press.
Vintage Books, an imprint of Random House, released it in early April. It has previously been a bestselling e-book after being distributed by the small Australia-based Writer's Coffee Shop Publishing House.
Vintage announced Tuesday reprints of the books have exceeded 900,000 copies in a single day - that includes paperbacks, e-books and audio books, the AP wrote.
In the 50 Shades trilogy, a wealthy, dominant man named Christian Grey, spanks, ties and flogs up and enters into an S&M relationship with a young college student, Anastasia Steele. It began on a fan fiction website inspired by the "Twilight" vampire series.
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Publishers Weekly reported that sales of "Fifty Shades of Grey" jumped 40 percent in the week before Mother's Day.
Film rights were acquired by Universal Pictures and Focus Features in March.
Currently, many famous stars have been spotted reading the books.
Charlize Theron and Kristen Stewart, co-stars in the film “Snow White and the Huntsman,” recently read from “Fifty Shades of Grey” during an interview with MTV.
Asked if she is familiar with the book, Stewart replied, ”I’ve seen people read this on airplanes. And I’m always like, ‘Eww. Take that blanket off your lap, you freak.’”
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