Black, white, red -- when you look as good as Jessica Simpson looks these days, every color is slimming. The fashion mogul, 33, is once again showing off her svelte figure in a new ad for Weight Watchers, this time in a sexy, body-hugging white dress.

The video, posted to the company's YouTube channel on Wednesday, March 5, features Simpson modeling a fitted Alexander McQueen sheath and talking about her post-pregnancy weight loss. "I really love going to [meetings]," she says in the clip. "It reminds me we don't have to do this alone. It's so much better to have some backup, and to do it together, because we all face similar challenges."

"I have a newfound determination that I'm really proud of," she adds, beaming. "I can honestly say I've never been happier."

Indeed, the mom of two (to daughter Maxwell, 21 months, and son Ace, 7 months, with Eric Johnson) seems to have a newfound confidence. "This body made two amazing little human beings. I love this body and what it's capable of -- no matter what size," she said in previous Weight Watchers ad. "But this version feels really good."