"Fifty Shades of Grey" is not only the most popular book in the world, but it's also becoming an object of obsession.

Victoria Beckham recently admitted that she's absolutely hooked on the sexy erotic novel, Entertainment Wise reported.

Beckham famously claimed that she had never read a book but, thanks to EL James' raunchy S&M novel, it seems as if the former Spice Girl has decided to brush up on her reading skills.

The steamy "Fifty Shades" trilogy, written by bestselling author E.L. James, tells the story of 22-year-old recent college grad Anastasia Steele, who enters into a dominant/submissive sexual relationship with 27-year old sexy billionaire Christian Grey, through an "agreement," and both explore the world of BDSM (bondage, dominance, submission, masochism).

"I'm halfway through the second one... I even bought my mum the book!"

Beckham has admitted to Glamour magazine that she has even given a copy of the x-rated novel to her mum, but doesn't want to brush the subject with her.

"I even bought my mum the book. But every time she tries to engage in conversation about it, I kind of dodge the subject. I don't really want to talk to my mother about S&M," said the former Posh Spice.

The star, who has three sons and a daughter with footballer husband David, said she would not rule out having another child, according to the Associated Press.

She said: "It's a juggling act - a career, family, a husband who's busy. But I'd never say never."

Who never knows what reading the spicy novels might do to increase family size?

"Fifty Shades of Grey" recently surpassed "Harry Potter" on Amazon.

"Fifty Shades of Grey," along with the other two novels, "Fifty Shades Darker" and "Fifty Shades Freed," sold more than four million copies in print and on Kindle since they went on sale in March, making James the best-selling author of all time at the U.K. website of Amazon.

The first novel is outselling JK Rowling's final installment, "Harry Potter and The Deathly Hallows," by more than two to one, according to The Sun.

Gordon Willoughby, EU director of Kindle, said, "If JK Rowling was the literary phenomenon of the last decade, then EL James looks certain to take that mantle in the current decade."

"In just four months, EL James has become Amazon.co.uk's biggest-selling author of all time, which is truly remarkable when you consider that we've been selling books for almost 14 years."