The actress, 26, tells the U.K.'s Daily Mirror that hubby Brian Austin Green's 10-year-old son, Kassius, is somewhat underwhelmed by the new arrival. (Kassius is Green's child with ex-girlfriend Vanessa Marcil, from whom he split in 2003, one year before meeting Fox on the set of Hope & Faith.)
"Kash is a little indifferent," the This Is 40 star says of Noah's stepbrother. "He's not experiencing any sort of jealousy or competitiveness, but he's not excited because he just wants to go play video games."
Green, on the other hand, is every bit the doting dad.
"My husband is amazing," Fox tells the Daily Mirror of her spouse, 39, adding that he's taken on the majority of the household chores since Noah was born. "He does more work than I do and he's just a champ...He's so helpful and nurturing and amazing...He's my soul mate."
In fact, a lot of things in the brunette beauty's life seem "meant to be" at the moment.
"I love [motherhood]," she says. "It's what I've wanted to do since I was a little girl."