"Fit is very, very important," the Spice Girl turned denim (and dress) designer tells the August issue of Teen Vogue.
"You want a jean that is superflattering but also relatively practical. You need to be able to move around in it. When I wear a skinny jean" -- and really, for Beckham, is there any other kind? --"I like it to have a little bag around the knee and the ankle. It's more modern than something that is tight, tight, tight."
And while she may be busy running a fashion empire, trotting the globe with soccer stud husband David Beckham, playing mom to three young boys, and acting as the new Creative Design Executive for Range Rover -- yes, you read that right -- Beckham still manages to keep her perfectly mascaraed eye on all those little denim details.
"I spend a lot of time making sure we get it right with the wash because there's a big difference between something that looks authentic and something that looks like it's been made," she explains.
Beckham's "fashion-forward and quite European" line has garnered a legion of celebrity fans, including "High School Musical" star Vanessa Hudgens, for whom the Posh one customized a pair of jeans, which the actress wore in Teen Vogue.
Taking gray jeans and a few simple, everyday household items like, oh, say, sandpaper, gray paint and silver leaf, a paint tray and mixer, and a bicycle tire -- you know, the kind of stuff you keep in your junk drawer -- the gals created dazzling denim that Hudgens modeled for photographer David Mushegain.
And it probably won't be long before Beckham is trying to get inside Hudgens's pants. "Everything that I design," she says simply, "I wear."
For more glittery denim, check out Katy Perry's embellished Daisy Dukes.