High-fashion models have long-since graced the covers of magazines and ruled the runway, always earning themselves the title of "most beautiful women in the world." But now there's a new set of supermodels stealing the show -- and they hail from Hollywood.

Jessica, Jada, Kate, Gwen and Jen are just some of the celebrities covering high-fashion magazines. And Kerry Diamond, beauty director of Harper's Bizarre, told us why: celebrity covers mean cash.

"The whole celebrity as supermodel trend has exploded over the past few years," Kerry told us. "They just have a much wider appeal across the country, people feel like they really know them."

So how much cash does a covergirl make? Well, Halle Berry's pay pales in comparison to her "Catwoman" fee of $14 million. "Actresses don't get paid anything," Kerry revealed. "They always do a cover to promote a project."

But Kerry told us the big money is made by doing print ads. Berry is the face of Revlon, Jennifer Lopez vamps for Louis Vuitton and Adrian Brody looks handsome in Zegna. And come this fall, Liv Tyler will pose in Givenchy, Scarlett Johansson and Hilary Swank will wear Calvin Klein and Nicole Kidman will show off Chanel.

"She's an Oscar winner and it makes perfect sense for her to go with a brand like Chanel," Kerry said of Kidman. "That represents all the elegance that she does."

Actresses also seem to be flaunting their looks on the cat walk this year. Christina Aguilera and Halle Berry took the stage this summer, and Mischa Barton posed for Tommy Hilfiger.

But don't kiss the supermodels goodbye for good. "Celebrities are more popular than ever, but when it comes to representing beauty brands, there will always be a need for models," Kerry insisted.