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!"

PHOTOS: Jessica Simpson's curve-hugging looks

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.

PHOTOS: Jessica Simpson's body evolution

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 pleasures every now and then, too)," she explained via Facebook on May 30. "I have actually gotten a group of friends together who are going to be doing it with me."

PHOTOS: Jessica Simpson's most outrageous moments

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."

MORE FROM WONDERWALL:

Celebs Who Put Carriage Before Marriage

Maternity Style: Hits and Misses

Hollywood's Most Powerful Moms