12/22/2014 08:58 EST | Updated 12/23/2014 03:59 EST

Jessica Simpson's Toned Legs Are Unreal (PHOTOS)

Looks like someone got ahead of their New Year's resolutions!

On Sunday, Jessica Simpson showed off her crazy toned legs on Instagram during a fun photoshoot.

The 34-year-old dressed up in a LBD with fringed sleeves in two sexy photos—one where she posed on her knees and another where she stood up.

FRINGE #happyholidays @kristingram - photo cred

Uma foto publicada por Jessica Simpson (@jessicasimpson) a

Jes accessorized her dress with black heels, dramatic smoky eyes and sleek locks. The mom—who gave birth to her second child in June 2013—has opened up about her new healthy regimen, which has involved Weight Watchers and regular workout sessions with fitness instructor-to-the-stars, Harley Pasternak.

So how does she get those killer gams? Tons of repetitive exercises, natch. "We usually alternate between doing quads one day and hamstrings and glutes or butt the next, and then inner thighs," Teri Ann Krefting, one of Pasternak's trainers, told People about Jessica's regular workouts. "She's obviously genetically gifted with those legs," Krefting continued. "She's got great legs no matter really what her weight is."

We couldn't agree more!

Mirrors and Fringe @kristingram #happyholidays 🙌

A photo posted by Jessica Simpson (@jessicasimpson) on

She looks amazing!

Photo gallery Jessica Simpson Through the Years See Gallery