"I've always been a girl's girl," Beckham, aka Posh Spice, said in a statement Thursday. "And I know from experience that making the very best of yourself is something any woman can do."

Beckham is a member of the newly reunited Spice Girls and wife of soccer star David Beckham.

"I was never the 6-foot-tall pinup. I've always been the girl-next-door who got lucky," she said. "I've come a long way in the last 10 years, but this book isn't my attempt to tell you what or what not to do. It's just to share some of what I've learned."

According to HarperCollins, "That Extra Half an Inch" will offer guidance on everything from how to dress on special occasions to "how to feel confident and look great every time you leave the house."

Beckham's ability to sell books, at least other people's books, has already been demonstrated. Last spring, she was seen holding a copy of "Skinny Bitch," a diet guide by Rory Freedman and Kim Barnouin that soon became a best seller.