The 38-year-old actress, who has a 11-month-old daughter, Olive, with her husband Will Kopelman, credits his mother Coco Kopelman for teaching her how to be a good person.
The 'Family Guy' star told UsMagazine.com: "She's the best. My mother-in-law is actually my muse, just on how to be a person and a wife and a mother."
The actress, who had a troubled childhood, is very close to all of Will's family and revealed her sister-in-law Jill is throwing Olive's first birthday party on September 26.
She said: "We have a little party going on for her, a little first birthday that my sister-in-law is throwing. I'm like Jill [Kopelman], take over!"
Drew is also besotted with her little girl and is proud of her daughter's best qualities.
She said: "She's a sweet person, which is all I care about. I am obsessed with nice. That's the most important thing."
The 'Big Miracle' actress recently revealed she wants another baby as she doesn't want Olive to grow up feeling lonely.
She previously said: "I was an only child, and it was lonely.
"Some people love it and thrive on the independence, but I want my kids to have other kids around. Maybe two kids so they can run around life together, roll their eyes at their parents together like Rusty and Audrey Griswold from ['National Lampoon's] Vacation'. So however that's going to come about, it's gonna happen!"