EXCLUSIVE: Kate Winslet, Milla Jovovich Get Their Baby Bumps Painted by Spanx Founder Sara Blakely

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Sara Blakely became the youngest self-made female billionaire in America after founding Spanx, and now she has a new passion -- painting celebrity baby bumps.

In her new book, The Belly Art Project, Blakely celebrates pregnancy by featuring more than 100 moms-to-be with their burgeoning bellies decorated in clever designs.

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"Some bellies took 15 minutes to paint and some bellies took two or three hours to paint," Blakely tells ET. "All of them were eight or nine months pregnant and actually a lot of them we painted on the due date. There were a lot of contractions going on."

Some of the moms featured in the book include Kate Winslet, Alyssa Milano, Milla Jovovich, Savannah Guthrie and Elsa Pataky.

"Kate did Earth on her own belly," Blakely recalls. "She was so particular about England being well represented that she actually grabbed the paintbrush and started painting her own belly."

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Some of the ladies went with numerous designs.

"Alyssa Milano did three looks," Blakely shares. "She did the peace sign, the snow globe and the baseball, because Alyssa Milano is really into baseball."

The book has been seven years in the making, as Blakely, a mother herself, was inspired by her own pregnancy with son Lazer.

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"The idea for the belly art project actually popped into my mind three days before I delivered my son," Blakely says. "I had this urge to turn my belly into objects."

All of the author's proceeds from the book are going to benefit Every Mother Counts, an organization that seeks to make childbirth safer for women around the world.

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