Jessica Simpson

Looking good, Jess!

She's got one of Hollywood's most talked-about bodies, and Jessica Simpson proudly showed it off while shooting a Weight Watchers ad in the California desert a couple months back. After giving birth to first child, daughter Maxwell Drew Johnson, back in May, the designer, singer and Fashion Star mentor, 32, successfully dropped 50 pounds on Weight Watchers.

In an outtake from the "Expect Amazing" campaign (which begins airing Dec. 25), the famous blonde looks radiant and slim in tight jeans, boots, low-cut blank tank top and plaid shirt. "Weight Watchers changed my relationship with food, and I feel so much more prepared to make the right choices," says the spokeswoman. "It feels pretty incredible.”

Of course, the star (who dropped the weight by sticking to her Weight Watchers points and four trainer sessions a week) is set to undergo another transformation: As reported exclusively by Us Weekly, Simpson is now pregnant with her second child.

"Jessica loves being a mom," an insider told Us. "She really is overjoyed."

(Simpson's rep had no comment regarding the second pregnancy.)