Hilary Duff Talks Kids' Book as Due Date Nears — and How Son Luca Is 'Helpful' with Sister Banks

Laura Moll @lauramollphoto Hilary Duff

Even as Hilary Duff's due date quickly approaches, she's busy promoting her kids' book inspired by her 2-year-old daughter Banks Violet, My Little Brave Girl, which published on Tuesday.

In a candid interview with PEOPLE, the Younger star opens up about her hopes for the book, what it's like to navigate a pandemic and her first year of marriage with husband Matthew Koma, how this third pregnancy is different from her past experiences — and how her kids, Banks and son, Luca Cruz, 9, are handling the imminent arrival of a new sibling.

"It's been so cool to be pregnant and have an almost 9-year-old," the soon-to-be mom of three, 33, explains via email. "[Luca is] super compassionate and understanding of the fact that I'm moving a little slower and don't have as much energy as normal. He's so helpful. He jumps to help me when something spills in the kitchen and also great with helping me with bags from the car."

She continues: "He's also explaining things to Banks when she doesn't understand what's going on or she doesn't get her way. I notice when she's acting like a 2-year-old, he's extra patient with her and begins to sound like me or Matt when he talks to her in an effort to help out or soothe Banks. Banks will kiss my belly, but she hasn't eased up on her daily expectations of me… It's her world and we're all just living in it!"

It's been a busy time for the actress. When she isn't filming, Duff is focused on taking care of Luca (whom she shares with ex-husband Mike Comrie) and Banks. She and Koma, who welcomed Banks in October 2018, wed in December 2019, just before the COVID-19 pandemic hit. They decided to keep the sex of their second baby, who is due any day, a secret — though Duff has a hunch the baby will be a boy. As does Luca!

"Luca knows what this looks like now from his experience with Banks," his mom explains. "He's super excited about the new addition — and hoping it happens on a weekday because he knows he gets to skip school!"

Keep reading for more about the star's upcoming book and her hopes for her growing family.

PEOPLE: What is the biggest lesson you want your daughter and other young girls to learn from My Little Brave Girl?

DUFF: That their future is boundless, to be brave and take risks, and to approach life with an open heart.

How did your childhood shape your understanding of the importance of friendship and self-discovery, which you highlight in the book?

I felt so lucky to have my childhood in the hill country in Texas. Most of my play was done outside with neighborhood kids, climbing trees and riding bikes. I had to use my imagination a lot — we didn't have a ton of toys. I think it shaped how I am today and how I raise my kids. I'm adventurous and we love to be outdoors! When it comes to friendship, I've always been the type to have a smaller group that sure do mean a lot — quality over quantity in that department. They have always been a support group and safety net for me. All of my friends are very different — different ages, different places across the country, different stages of their lives — I'm constantly learning from each one of them.

Random House Books for Young Readers

Have you started writing your second picture book?

Don't tell my publisher, but no! I have some loose ideas and an understanding of what I want it to be, but it hasn't all come together yet.

How is this pregnancy different from your previous ones?

Shooting a TV show during a pandemic will really take your mind off of it! Also having two other children to focus on, keep on schedule, fed and clothed is like a juggling act and I didn't have time to google every stage of my pregnancy like I have in the past. It's gone by very fast and been uneventful which I feel lucky for.

What is your favorite way to spend quality time with your kids, especially as you navigate work and living in the pandemic?

Bath time and bedtime routine will always be my number one way to get quality time with my kids — giggles, snuggles and cuddles, funny songs we make up, and dances. Don't get me wrong, there are days that go on forever and completing that whole process after dinner feels utterly exhausting, but the payoff is always so rewarding. I feel so lucky that we have a great backyard, and that we get a lot of quality time together there in the sunshine!

Ashley Barrett The actress

How has your relationship with Matthew been challenged and strengthened during your first year of marriage?

We talk about it often, how we have really grown together in big ways during the first year of marriage. I don't know anyone that I've had guidance from in my lifetime deal with a worldwide pandemic during their first year of marriage and still be as happy as we are. We have had to work some kinks out, but it's been very productive. We have a really great thing — we are very kind and loving to one another. He's constantly reminding people, especially Luca, that I'm the anchor of this family. I'm so grateful that he's as funny as he is… but we're still working on his wet towels on the floor!

With two kids, dogs and being pregnant how are you handling everything? Do you ever feel overwhelmed?

You forgot the five chickens and the gecko, who in my opinion is on the brink of death every day! Sure, there are times that I feel overwhelmed, but I have two wonderful women who also support this household and all of the mayhem that we create. Sometimes I feel like there are never enough hands-on deck or THERE'S NEVER ANY TIME but for some reason I operate best when the plate is completely packed.

RELATED VIDEO: A Timeline of Hilary Duff and Matthew Koma's Romance

What is your biggest hope for your expanding family?

Deep respect for everyone as an individual, a loving support system, many wonderful memories, endless kindness, and to raise hard working, compassionate individuals… plus, we needed one more to help out with the chicken coop!

How do you find time for "me"/self-care time when you aren't pregnant?

My time for myself is a workout after I drop the kids off at school or a bath in the evening. It's been tougher to organize during the pandemic, but time with my girlfriends rejuvenates me and helps me feel like a human being outside of my kids' lives or my career. Usually best enjoyed with wine!

My Little Brave Girl is on sale now.