What do Kate Middleton and Emma Thompson have in common, besides being beautiful, brainy Brits? Their trainer! Louise Parker works with them both, and Thompson loves her so much, she penned the forward for the personal trainer and dietician's book, The Louise Parker Method: Lean For Life.

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"Louise is the only one out there I trust," Thompson writes in the introduction, according to the Daily Mail. "She's not holier than thou, yet somehow miraculously gets my reluctant arse into gear and sometimes even keeps it there."

The proof is in the (probably low-calorie) pudding: Thompson says she has lost two dresses—down from a size 10 to a size six in less than two months—thanks to Parker's "fad-free" weight loss plan.

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"I love that her method is NOT a diet—and is genuinely sustainable—so I can have my glass of wine and manage to avoid spending the rest of the week eating cheesy Wotsits," the actress continued. "She toughens me up without driving me round the bend with kale juice and the more depressing style of sprout. She just gets it. We all use her, because she's discreet and funny and that's really important."

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We're guessing the Duchess feels the same way; Parker worked with her after she had Prince George. So, where do we sign up?

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Taysha Murtaugh
Lifestyle Editor

Taysha Murtaugh was the Lifestyle Editor at CountryLiving.com.