Jessica Simpson’s trainer said a key to the star's recent 100-pound weight loss was a simple nightly check-in designed to foster accountability.

Harley Pasternak, who has worked with Simpson for more than a decade and helped her drop weight after all three of her pregnancies, explained that he gave the actress a series of daily tasks and asked her to report in whether or not she completed them.

“We had a nightly email [check-in],” he told Us Weekly. “And so my clients, before they go to bed at night, send me an email and it says, Did you hit your step goal? Yes or no? Did you hit your sleep goal? Yes or no? Did you hit your unplugged goal? Yes or no? Did you hit your food goal? Yes or no? To the extent that you check yes, it gives you this sense of accomplishment at the end of every day.”

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Despite setting clear goals for the “Employee of the Month” actress, Pasternak notes that it was her own dedication to a healthy lifestyle that’s to credit for her immense weight loss after giving birth to daughter Birdie in March. For example, he noted that keeping her from exceeding her step-goal was the real challenge.

“Shortly after she gave birth, as soon as we got medical clearance to start walking,” he explained. “We had a daily step goal on her Fitbit. More of a limit if anything because we didn’t want to do too much.”

Simpson initially set out with a goal of 6,000 steps per day, but he says she was up to 14,000 very quickly.

Pasternak previously discussed Simpson’s commitment to weight loss after giving birth in a September interview with People.

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“The difference between this and the other times was that she worked out, yes, but her transformation was more about what she did on her own time,” he explained. “She was so motivated and positive. She was saying that her body has not belonged to her for the past decade. Not in a bad way, in a positive way — her body has been designated to create life and now it’s hers again and she’s going to make it fantastic in a really enjoyable way.”

Simpson, who is mom to Birdie, Maxwell, 7, and Ace, 6, showed off her results in an Instagram post last month with a photo of herself rocking an all-black outfit.

"6 months. 100 pounds down (Yes, I tipped the scales at 240 😜)," she wrote.

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“My first trip away from #BIRDIEMAE and emotional for many reasons, but so proud to feel like myself again," Simpson said. "Even when it felt impossible, I chose to work harder. 💚"