The blonde beauty shared a snapshot on Instagram on Thursday, posing for her clothing line's Spring 2014 campaign.
The mother-of-two looked fit and fabulous in a white one piece, retro-inspired swimsuit that showed off her post-pregnancy curves. She topped the look off with a pair of oversize pink sunglasses and Brigitte Bardot-esque tousled hair.
The 33-year-old has been raving about her diet plan with Weight Watchers, and she recently said that her upcoming wedding has given her an incentive to stay slim.
"The new year will definitely bring on the wedding bells, which is exciting…I think it's about time,"she told People magazine.
"Knowing that I have the wedding coming up is an incentive to stay on Weight Watchers, count my points and stay in the gym," Simpson added. "I mean, when you see my dress, you'll know!"
We can't wait to see Jess walk down the aisle!
What do you think of her bathing suit selfie? Tell toofab in the comment section below, and click "Launch Gallery" above to see more celebrities' post-baby bodies, before and after!