KARACHI: The “Fifty Shades” trilogy, “Fifty Shades of Grey”, “Fifty Shades Darker” and Fifty Shades Freed”, all by British author E. L. James, is doing spanking business at bookstores, shattering Harry Potter's record and selling around 20 million copies worldwide.

All age groups, from married couples to teenagers are devouring the book. It's the dirty talk of the town — be it college canteens, kitty parties or dark bedrooms.

It has offered bedroom inspiration to women around the world and now teenage girls as young as 14 are being swept up by the “Fifty Shades of Grey” mania.

Not only adults, but the erotic novel has piqued the interest of students as well.

According to media sources, teenagers are reading the book unbeknownst to their parents and despite “mature audience” warning stickers being placed on many of the hard copies being sold the young readership is growing.

Fifty Shades of Grey is making waves as it debuts at the Comic-Con annual festival and response to it has been quite massive.

Media sources said fans lined up early for the Thursday afternoon book signing and the chance to meet E. L. James, the woman behind the phenomenon of Fifty Shades. Within one hour, all 300 tickets had been snapped up.

Fans of the series have been on the edge of their seats, waiting impatiently to find out who will play the roles of Ana Steele and Christian Grey in the movie adaptation.