Credit: Jemal Countess/

Victoria Beckham's not-so-dirty little secret to her super-sleek physique: hitting the gym seven days a week.

"I didn't want to rely on retouching," the fashion designer and former Spice Girl, 35, says in the December issue of British Harper's Bazaar.

Her flawless appearance in recent Emporio Armani ads with soccer-star husband David led some to suspect airbrushing.

"I wanted to look at those pictures in 20 years' time and say 'Wow, look -- after three kids -- I didn't look bad,'" the gym devotee says.

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Despite her intensive gym routine, however, not all of Posh's body is completely bonafide. Several pals have confirmed to that Beckham has undergone breast surgery three times: two enhancements and, earlier this year, a reduction.

"She's not the most confident of girls, believe it or not," a Beckham confidante recently told Us.

What of Botox? "She has not had any botox or fillers," the friend says. "She's squeamish about things like that and doesn't want to mess up her face."