JESSICA Simpson gained 70 pounds (over 31 kilos) during her pregnancy.
The singer, actress and fashion designer piled on the weight while she was carrying her daughter with fiancé Eric Johnson, Maxwell.
Apparently Jessica - who has become a spokesperson for the Weight Watchers brand - had her first weigh in a few weeks after giving birth on May 1.
The 32-year-old star signed a deal for $4 million to shed the excess weight as face of the company.
Her contract requires a 20 to 30 pound loss (about 9 to 13 kilo loss) by the end of August or she will reportedly not receive the agreed amount.
A friend of the ambassador told website UsMagazine.com: ''Jessica has always had issues with junk food.''
The 5-foot-3 'Fashion Star' mentor is rumoured to have enlisted her mother, Tina, and a few friends to do the program ''to help keep herself in check,'' according to the insider.
Jessica, who plans to breast-feed through July, also ditched her beloved high-calorie margaritas, claims the close source.
The insider added about her healthy new diet regime: ''She had a few drinks post-pregnancy, but then stopped.''