Jessica Simpson is showing off her post-baby body in a sexy swimsuit for her clothing line JS Collection. The singer-turned-fashion designer retweeted a picture of herself in a white halter one-piece bathing suit posing by a pool, the New York Daily News reports.

The 33-year-old mother of two has been using Weight Watchers to slim down and drop the baby weight after giving birth to her son Ace Knute Johnson in June. She already has a daughter, Maxwell, with her fiancé Eric Johnson.

"I'm a lot more confident this time around," she told MomFeeds in October. "With Maxwell I didn't think about the weight I was gaining, and the first time I stepped on a scale and looked at the number... I mean, that wasn't a number I had ever even considered... and I was faced with a pretty serious truth."

"But since I had already done Weight Watchers, I didn't put on as much weight with Ace," she continued. "And I just know a lot more now."

A friend close to Simpson told US Weekly that she was treating her second pregnancy a lot different and had hired a chef to cook her nutritious meals.  

"The chef is there all day," the friend said. "Jessica eats things like egg whites and sausage. It's healthier."

On the "Ellen DeGeneres Show" in March Simpson revealed that she ate whatever she wanted while she pregnant with her daughter but with Ace she was paying close attention to her food choices.

"The first pregnancy, I like, let loose and I kind of ate everything that I wanted to eat and I just really enjoyed it," Simpson said. "This time around I think because I was doing Weight Watches and I felt super healthy I'm not really craving as much as I know how hard it is to get off, so I'm trying to make healthier, wiser decisions."