Jessica Simpson Shares Post-Workout Selfie -- and She's Looking Super Fit!

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Jessica Simpson is working on her fitness in quarantine! The 39-year-old singer took to Instagram on Wednesday to share a post-workout mirror selfie.

In the sweaty shot, Simpson rocks a tie-dye sports bra with matching high-waisted shorts and a coordinating headband. The impressive pic shows off Simpson's toned abs, arms and legs.

"Woke up before all 3 kiddos to get my steps in and spend time with me, myself, and I," she wrote alongside the photo referencing her three kids, Maxwell, 8, Ace, 6, Birdie, 1. "Move move move for your own mental health."

Last year, ET caught up with Simpson's trainer, Harley Pasternak, who revealed how the mom of three lost 100 pounds after giving birth to Birdie.

"She lost the weight because of everything she did when she wasn't in the gym. Of the 168 hours of the week, she's only working out around three of those," he said, adding that Simpson makes it a point to walk 12,000 to 14,000 steps per day.

The weight loss came after Simpson struggled with body image issues for years. In fact, in her memoir, Open Book, Simpson revealed that she previously underwent two tummy tucks.

"I was so ashamed of my body at this point that I wouldn’t let Eric see me without a white T-shirt on," Simpson wrote of her husband, Eric Johnson. "I had sex with it on and even showered with it on. I couldn’t bear to look at myself."