NEW mom and Weight Watchers spokesperson JESSICA SIMPSON has already lost more than 40 pounds, but she still has a long way to go! And she’s having such a tough time losing her excess baby fat that she’s telling pals she wants to turn to liposuction to help get her figure back!

The 5-foot-3 “Fashion Star” – who was in talks with the popular diet program before the May 1 birth of daughter Max­well Drew – debuted her post-baby body on the Sept. 10 premiere of Ka­tie Couric’s new ABC talk show.

The onetime bombshell hid her curves under a black, stretch-crepe Roland Mo­uret dress that sells for almost $3,000! The peplum waist helped hide her extra weight and sources say she wore extremely binding undergar­ments to make her look thinner.

“Jessica’s weight exploded to over 200 pounds while she was pregnant,” a source revealed. “She thought losing it after giving birth would be a breeze, but Jess was in for a rude awakening.”

During her appearance on “Katie,” Jessica was vague about exactly how much she’d lost, saying only that it was “more than 40” of the 70 pounds she’d gained during her pregnancy.

According to the source, she’s managed to get down to 155. Compare that to just seven years ago, when the blonde beauty whittled her voluptuous physique down to 100 pounds for her role in “The Dukes of Hazzard.”

Jessica’s $4 million, one-year contract with Weight Watchers reportedly stipu­lates that she would forfeit payment if she didn’t lose 20 to 30 pounds by the end of August and 70 pounds within a year.

But Jessica’s target weight has continued to tick upward – from 130 to 135 to 145 – as she’s struggled to shed the pounds. While the com­pany remains committed to Jessica’s success on the program, the 32-year-old star has publicly admit­ted that slimming down is much harder than she ever imagined it would be.

“Jessica is working hard to stay focused and keep up her willpower. She does a good job dieting most days. She follows her diet points, exercises and tries to get her brain into the diet zone. But it’s not always easy. Privately, Jess has mo­ments when she’s so distraught that she tells pals if she doesn’t lose more weight by counting calories, she’ll have liposuction when her Weight Watchers contract is up,” said the source.

According to insiders, Jessica – who’s engaged to former NFL player Eric Johnson – feasted on up to 3,000 calories a day while she was pregnant. But over the past few months, she’s been pushing herself to her limits to get back in shape and is finding it incredibly difficult. She’s already looking for a shortcut.

“She’s never been into exercise, so the killer workouts are especially grueling for her,” the source added. “And for someone who gorges on fried chicken skin and mac and cheese and who thinks butter is one of the major food groups, the diet has been the hardest work of Jess’ life.

“She’s admitted to a few close friends that if she knew then what she knows now, she would have passed on Weight Watchers and just had a quick nip and tuck.

“Jessica wants to stick to her weight-loss routine, and hopes that one day she’ll start to like it.

“But if her ac­tions after the Katie Couric show are any indication how much she en­joys dieting, Jessica has a long row to hoe. Immediately after leaving the studio, Jessica went to a local restaurant with a group of friends for lunch.

“Rather than order a small, health-conscious meal, she picked off her pals’ plates, indulging on thin crust pizza, antipasto, assorted olives, flat breads with olive oil and even orange gelato for dessert.”