The singer-turned-clothing-designer graces this week's cover of Us Weekly with the 2-month-old in one arm and 15-month-old daughter Maxwell in the other.
"With two kids, we have our hands full, but every day is a new adventure," Simpson told the magazine. "It's fun! I feel very at peace with being a mom."
The family posed for the shoot at their Hidden Hills home on Aug. 12. For the cover, little Ace, born May 30 via
Missing from the cover shot was Simpson's fiancé, former NFL player Eric Johnson, to whom she's been engaged since November 2010, though he's reportedly also featured inside the mag, which hits newsstands Friday.
Jessica clued Us into her family plans, saying she wants to hold off on expanding her unit, for now anyway. "Pregnancy is a lot. It was hard to do two so close together," she said. "I have this huge sense of accomplishment, and I feel in my heart that I'm done. But obviously, accidents do happen!"
And speaking of the unintentional, we found out the gender of her baby on
"I've been vomiting and the crazy thing is I never knew that a wiener could actually make me nauseous," she said in good spirits. "Oh, shoot, I guess I just told the world that I'm having a boy!"
It's the Jessica we've come to love -- or, well, not so much.
Before the baby arrived, sister Ashlee Simpson threw a Tom Sawyer-themed baby shower for Jessica. "He got all these cute vintage cars and I got a lot of little leather jackets I can't wait to try out!" Jessica said of Ace's goodies.
And now she can! Please Instagram them for us, OK?