The singer/fashion mogul Tweeted a photo of herself Tuesday looking even more svelte just prior to an appearance on Good Morning America.
"Good Morning, America! Going live soon! #weightwatchers" she wrote while referencing her gig as a pitch woman for the weight loss brand.
The accompanying photo showed Simpson, 33, looking trim and fit (check out those arms!) in a fitted black dress and heels.
It's the latest in a series of photos that show how quickly Simpson's much-scrutinized figure has bounced back after welcoming her second child – son Ace Knute – six months ago. He joined older sister Maxwell Drew, 18 months.
Simpson recently told USA Today she is back down to her pre-pregnancy weight, thanks to Weight Watchers and her frequent sessions with personal trainer and PEOPLE blogger Harley Pasternak.
That surely comes as a triumph for Simpson, who recently confessed to Redbook that the attention surrounding her pregnancy weight gain was difficult.
"I think any woman who is pregnant and creating a life is pretty much entitled to eat whatever she wants as long as she's healthy," she told the magazine. "I wasn't going to let the media take away from what was one of the happiest times in my life."