Celebrity Jessica Simpson Wore the Sexiest LBD for a Girls' Night Out By Brittany Vincent Brittany Vincent Brittany Vincent is a writer with 15 years of experience reporting on celebrity news and entertainment. InStyle's editorial guidelines Published on September 26, 2019 @ 06:15AM Pin Share Tweet Email Jessica Simpson is looking and feeling her best after revealing she lost 100 pounds since welcoming her third child, daughter Birdie. The pop star took to Instagram with a stunning photo of her standing outside of her New York City hotel room in a curve-skimming little black dress that showed off her trim new shape. "NYC Ladies’ Night ✨," Simpson captured her photo. Jessica's sexy new LBD is an eye-catching piece with a dramatic thigh slit that looks sizzling paired with dark tights. On Tuesday, Simpson shared images of her post-pregnancy weight loss alongside captions indicating that she had reached a weight of 240 during her third pregnancy. Over the course of six months, she worked hard to "feel like herself again," she said. “6 months. 100 pounds down (Yes, I tipped the scales at 240 😜),” she wrote on Instagram and Twitter. “My first trip away from #BIRDIEMAE and emotional for many reasons, but so proud to feel like myself again. Even when it felt impossible, I chose to work harder. 💚.” The "With You" singer showed off her figure in a few full-length body snaps, posing with Birdie and grinning from ear to ear. Celebrity trainer Harley Pasternak commented on Jessica's achievement while working with him as he headed to Instagram to congratulate her on her hard work paying off so well. "Beyond proud of this incredible woman," he wrote. "Been working together for over 12 years and she’s always the most warm, sweet, polite, and respectful person in the world. And on top of it all, after being nonstop pregnant for as long as I can remember, she’s down 100 pounds and looks younger today than she was when we met." Jessica Simpson's Foot Won the 10 Year Challenge Simpson has three children with husband Eric Johnson: Maxwell, 7, Ace, 6, and now little Birdie. Simpson had been vocal throughout her pregnancy about her various body concerns and methods she used to stay looking her best. She previously shared a special green tea skin mask she used to mitigate face swelling during her pregnancy and also worked with Motherhood Maternity for a new clothing line that's still totally wearable following pregnancy. She even turned to cupping in a bid to alleviate some of the ankle swelling she experienced while pregnant. In her new photos, Jessica is looking happier and healthier than ever, and little Birdie Mae keeps getting cuter, too.