The sexy romance "Fifty Shades of Grey" doesn't open until Valentine's Day weekend, but it already has movie fans hot and bothered. The much-anticipated adaptation of E.L. James' steamy bestseller is the fastest-selling R-rated movie in the 15-year history of Fandango, the online ticket broker reported Friday.

In its first week of availability, Universal Pictures' erotic love story starring Dakota Johnson and Jamie Dornan has outstripped sales for R-rated blockbusters "Sex and the City 2," both of "The Hangover" sequels and "Gone Girl."

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"Very few books can claim true national phenomenon status – and 'Fifty Shades' ranks with 'Twilight,' 'The Hunger Games' and 'Gone Girl' as novels that entered the zeitgeist from coast to coast," said Dave Karger, chief correspondent at Fandango.

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"Fans of the book have been waiting for years to see their favorite sexy characters come to life on the big screen, and they are clearly fueling the sensational advance sales."

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"Fifty Shades" has yet to come on tracking, but BoxOffice.com is predicting a $60 million first-weekend haul for the tale of a young woman's introduction to erotic submission.

Sam Taylor-Johnson directed from an adaptation by Kelly Marcel. "Fifty Shades" has a $40 million production budget and was backed by Michael De Luca Productions, Trigger Street Productions, Focus Features and Universal. Dana Brunetti and DeLuca are the producers.