Jessica Simpson shows off her weight loss in an upcoming Weight Watchers commercial. Credit: Youtube/WeightWatchers.

While Jessica Simpson has remained mum about reports that she's pregnant again, the new mom and Weight Watchers spokesperson is ready to show off her 50 lbs. weight loss.

Simpson, who gave birth to daughter Maxwell Drew in May, reveals her slim figure in a new commercial for Weight Watchers. The ad is slated to debut on TV Christmas day, but you can check it out online now.

"I didn't need to be perfect to get here, to lose over 50 pounds on Weight Watchers," Simpson says in the ad, clad in cowboy boots and driving a pickup truck. "I love food, I love life, and I had no idea I could be so in control and so free at the same time."

Simpson celebrated her pregnancy - near the end of it, she posed nude for Elle magazine and admitted she weighed 170 pounds - and she's been similarly vocal about battling the baby bulge. In September, she told Katie Couric that little Maxwell is part of her weight loss regimen.

PHOTOS: Jessica Simpson Through the Years

"I basically take her with me, whether it's strapping her on me or strolling around the neighborhood," Simpson said. "My new goal is 14,000 steps a day."

But food cravings remain one of her biggest obstacles.

"I feel like what made me eat more is my hormones and breastfeeding," Simpson said on "Katie." I've never wanted chocolate more in my life," she said. I've had to really stay focused and focus on my diet and concentrate on what I'm putting in my body."

The Dec. 25 ad will be Simpson's second for Weight Watchers. She's also been chronicling her weight loss through Twitter snapshots. On Halloween, she shared a photo of herself in a waist-cinching milk maid's costume.

RELATED: Is Jessica Simpson Expecting Again?