Jessica Simpson just showed off her post-pregnancy body on social media, revealing her 100-pound weight loss since giving birth to her third child, Birdie Mae, back in March.

The singer and fashion designer celebrated the achievement on Tuesday (September 24) via Instagram, telling her fans she was 240 pounds while pregnant with her baby. She posted two photos — one that shows off her svelte figure in a black figure-hugging dress and another that sees her posing with her daughter.

"6 months. 100 pounds down (Yes, I tipped the scales at 240)," she wrote on Instagram before revealing she took her first trip away from her newborn. "Emotional for many reasons, but so proud to feel like myself again."

"Even when it felt impossible, I chose to work harder," Simpson added.

In the comments section, Simpson's celebrity friends praised her health accomplishment.

"Gorgeous!!!!" RHOBH star Kyle Richards wrote.

"Wowza lady, you look [strong emoji] [bomb emoji]," Mad Men actress January Jones added.

Even her brother-in-law, Evan Ross, commented, "U look amazing sis."

The 39-year-old opened up what she's been doing to get back in shape, telling People, "I am working really hard right now. It’s not easy at all, but I am determined to feel good. I have been doing a lot of walking — getting my steps in not only burns calories but it also helps me clear my head and get focused."