The cute snapshot the designer revealed had a personal touch, revealing two different photographs edited next to each other. The black and white pictures had "3 MONTHS" written on it and showed the blond beauty holding Ace close, with the bright-eyed boy looking straight at the camera.
Simpson, 33, first debuted the new addition to the family exclusively to Us Weekly in August alongside big sister Maxwell, 17 months. "With two kids, we have our hands full, but every day is a new adventure," Simpson told Us at the time. "It's fun! I feel very at peace with being a mom."
Simpson officially signed back on with Weight Watchers in August. She reportedly earned $4 million in May 2012 in her first deal with the weight loss company while pregnant with Maxwell. Six months later, it was revealed that she was pregnant yet again with baby Ace!
Click on for more photos of Jessica, Ace, her daughter Maxwell and more family members...