Jessica Simpson is back down to her fighting weight and she wants the world to know it!

The "With You" singer, 33, posted a new selfie to Instagram over the weekend, showing off her svelte post-baby figure.

"Couldn't stop smiling on set for my new @weightwatchers campaign today! #happy," the fashion magnate wrote.

In the pic, Jessica is walking in a field, sporting skin-tight jeans, a white button-down shirt, and a grin that could light up a whole neighborhood.

[Related: Bring on the Daisy Dukes: Jessica Simpson Returns to Weight Watchers]

The mom of two, 33, had put her campaign with Weight Watchers on hold for almost a year during her pregnancy with son Ace Knute, who was born in June. In September, the company confirmed to omg! that Jessica was back on board.

"We were thrilled to welcome Jessica back on the Weight Watchers program in August," said a spokesperson for the weight loss company. "With a toddler on the run and an infant to look after, we know she needs a plan that's simple and fits into her life along with the support that's so important to moms with young children."

Jessica, whose fashion empire is worth a reported $750 million, began her deal with Weight Watchers — for a reported $4 million — in May 2012 after she struggled to lose weight following the birth of her first child, daughter Maxwell. She dropped more than 40 pounds during that summer, but soon became pregnant again and ended up putting the campaign on hold last December as a result. The company announced then that she'd continue as a brand ambassador in 2013 until she could get back to counting points.

In September, she responded to Us Weekly about folks who've criticized her for gaining weight due to her pregnancy. "I will never understand why people give pregnant women such a hard time," she said. "We are creating a human life: I think we get every excuse in the world to eat a doughnut!"

She continued, "I am definitely one of those pregnant women who just gains a lot of weight. I have really big boobs, I have my curves and I just gain weight. I can't help it … It's been six weeks since I've had my baby now, and I feel great … It's OK to gain weight, and it will always come off."

We think Jessica has never looked better! Now we'd love to see her get back to making music. What do you think? Should Jessica put out another album now that "Fashion Star" is off the air and she's through her second pregnancy? Sound off in the comments below.