Jessica Simpson to Weight Watchers Group: "Let's Step It Up!"

Jessica Simpson won't be fighting her weight war alone.

The new mom, 32, is hoping to inspire her pals to slim down with her -- though it's safe to assume they don't have a $4 million Weight Watchers contract as an added incentive. "Just bought all the girls in my Weight Watchers group pedometers to track their steps," Simpson tweeted July 19. "10,000 steps a day = 5 miles! Let's step it up!"

Simpson's contract requires a 20- to 30-pound loss by the end of August or no payday, a source recently told Us Weekly. The Fashion Star mentor -- who welcomed daughter Maxwell Drew with her fiance, Eric Johnson, 32, May 1 -- is also breast-feeding and training with pro Harley Pasternak.

The 5-foot-3 Texas native decided to team up with Weight Watchers because "it focuses on healthy habits for the long-term (and I can still indulge in my guilty plea sures every now and then, too)," she explained via Facebook May 30. "I have actually gotten a group of friends together who are going to be doing it with me."

The months ahead won't be easy for Simpson, who a source says "always had issues with junk food." Still, the new mom is determined to lose weight, which is why she enlisted her mom, Tina, and a few pals to join the program and "help keep herself in check."