Jessica Simpson Post-Pregnancy Body: First Photo!

Jessica Simpson has her work cut out for her if she's serious about dropping the pounds gained during her pregnancy with daughter Maxwell.

We're not being critical of Jess - it's not her fault the huge baby (9 lbs., 13 oz.) caused her to put on an estimated 75 pounds - it's just true.

On Tuesday, the 31-year-old was once again spotted hitting a gym in Los Angeles, giving us our first glimpse since she gave birth in May:

Heading into an SUV, Simpson (who's engaged to Maxwell's dad Eric Johnson) wore black leggings, tracksuit hoodie and cross-trainers.

The singer and fashion mogul was first spotted hitting the private gym of celeb trainer Harley Pastermak last week, with a lot at stake.

At the time of Elle's Jessica Simpson nude cover shoot, the 5-foot-3 star said she weighed 175 pounds. Her goal? Get close to 100.

Her motivation: A $4 million deal with Weight Watchers.

"She hasn't even thought about working out for a year!" a source told Us. "But if she wants this, she'll need to work out a good five days a week."

For four million bucks, she might even make it six.

[Photo: Pacific Coast News]