Nicole Richie and Kate Hudson share more than just a free-spirited demeanor!

The fashion designer, 30, and the Something Borrowed star, 32, have both received implants from Beverly Hills plastic surgeon Garth Fisher, several insiders confirm to Us Weekly.

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Fisher -- whose celebrity clients include Olympian Bruce Jenner and his business-minded wife Kris -- first performed Hudson's breast augmentation in March 2010.

"Kate makes jokes about her boobs, but her chest has always been one of her biggest insecurities," a source explained in April 2010 of her decision to go under the knife.

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Richie, meanwhile, had other reasons for getting her boobs done this summer.

"In the past, she said she wanted a lift, though we never thought she was serious," an insider tells the new issue of Us Weekly (on newsstands Friday).

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Adds a second source: "The pregnancies took a toll. She said breast-feeding killed what boobs she did have!"

Fisher has not responded to request for comment.

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