The American actress posed with new arrival Ace and daughter Maxwell for the magazine, and gave an exclusive interview about her growing family.
In the pictures Ace, whose full name is Ace Knute Johnson, is snuggled up in his mum's arms, alongside big sister Maxwell, 15 months.
Speaking to the magazine about having another newborn, Jessica said: "With two kids, we have our hands full, but every day is a new adventure. It's fun! I feel very at peace with being a mom."
Ace was born via C-section on June 30.
The full interview and photos appear in the September 9 edition of US Weekly.