Newly engaged Kim, 33, posted this picture of herself on Instagram, along with the caption "Work day".
Wearing a sheer crop top which flashed her black bra underneath, Kim's teeny tiny waist is clear to see, not to mention her toned arms and all-round healthy glow.
She and the rest of the Kardashian clan had been busy on a family photo shoot in Malibu and, in true reality star style, they were all quick to upload pictures of themselves looking glam.
Kim's been busy overhauling her diet ever since she settled into life as a new mum, and wasn't seen in public for months after the birth of baby Nori.
She's lost an impressive 50lbs - that's over 3.5 stone - by following the low-carb Atkins diet.
Kim has also been working out with celebrity trainer Tracy Anderson, who has helped to hone the bodies of Gwyneth Paltrow and J.Lo.
Kim recently told how hurt she'd been by cruel jibes about her weight gain while she was pregnant, telling Jay Leno: "It changed how I am in public a little bit... There were these stories where I was, like, 200 pounds.
"I was gaining weight because I was pregnant and it was really hard to read all these stories and hear all these nasty things."
She also admitted that the infamous selfie, where she posed white lingerie and showed off her gravity-defying bum, was her way of proving the haters wrong.
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