"I love Mother's Day and celebrating all the women I love," Liv Tyler tells PEOPLE exclusively in an interview about her new short film Mama Said for Gap
Each product we feature has been independently selected and reviewed by our editorial team. If you make a purchase using the links included, we may earn commission.

“Mama said … ” is something most people have probably heard countless times throughout their childhoods. But it takes on a whole new meaning for women who grow up and become parents themselves.

This is the message behind Mama Said, a new short film starring Liv Tyler, Jurnee Smollett-Bell, Candice Swanepoel and Coco Rocha. Launched by Gap in support of Every Mother Counts — a nonprofit organization founded by Christy Turlington dedicated to making pregnancy and childbirth safe for all moms — Mama Said features these celebrity mamas and their kids, outfitted in the brand and sending a message ahead of Mother’s Day about the importance of celebrating global motherhood.

“I love Mother’s Day and celebrating all the women I love. Mothers of humans, animals and friends,” Tyler — who also co-directed the film, on whose set she brought daughter Lula Rose, 9 months, and son Sailor Gene, 2 — tells PEOPLE exclusively.

“It was such a treat to be with all these incredible moms and children and to watch the children play and be so free in front of the camera,” adds the star, 39. “It was so magical to get to share the day with them. It made being on set so exciting. Something I will treasure always.”

Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Babies newsletter.

Credit: Courtesy Gap
Credit: Courtesy Gap
Credit: Courtesy Gap
Credit: Courtesy of Gap

Tyler has been a fan of Gap for a very long time, so the partnership was a natural fit, according to the mom of three (son Milo is 12).

“It’s always been an iconic brand I associate with my childhood,” the Empire Records actress tells PEOPLE. “I have done two Gap ads throughout my career, and was excited to do a special Mother’s Day film with my children.”

Speaking of her little ones, Tyler — who is busy with her own fashion ventures, having collaborated recently on designs with British brand Belstaff — says “I cherish every second with them.”

“Milo and I watch Sherlock reruns at night after homework. Sailor and I read books (Slinky Malinki) in our new chair — it’s so comfy!” she shares. “And Lula and I love to snuggle. Today, we took a secret nap for an hour and a half. I was 30 minutes late for a meeting, but so happy I had that special time with her.”

Gap babiesCredit: Courtesy Gap
Credit: Courtesy Gap
Credit: Courtesy of Gap

Tyler explains that her two littlest ones have quite the distinct personalities, which is something she fully embraces and appreciates.

“Sailor Gene is a complete original! He likes to do exactly what he wants,” she says. “He definitely has a natural performer’s personality. It’s so fun watching them develop into their own amazing people.”

She adds, “We call him a mini Sid Vicious because he has a bit of punk in him.”

Credit: Courtesy Gap
Credit: Courtesy Gap
Credit: Courtesy Gap

FROM COINAGE: Right Now Is the Best Time to Buy Winterwear — Here’s Why

As for her daughter, Tyler says, “My sweet Lula is so precious to me. She is truly gorgeous inside and out.”

“She is so different [from] the boys, and seems to have a natural grace and poise,” the actress explains of her youngest child. “I’m so grateful to be her mommy.”

Tyler admits she has loved having a little girl around — including the fashion bonuses. “I love dressing her in gorgeous girls clothes. It’s so fun,” she says. “The Gap had some beautiful classic pieces I just loved.”

Credit: Courtesy Gap
Credit: Courtesy Gap
Credit: Courtesy Gap

That doesn’t mean Lula is clad in dresses 24/7, though. As most parents who have more than one child know, there are plenty of clothes to go around already in the house.

“I have been buying her lots of sweet classic girl things, but secretly I’m really enjoying seeing her in Sailor’s boyish hand-me-downs,” Tyler confesses. “She looks so sweet in a pair of overalls and a plaid shirt.”

Contributions to Every Mother Counts can be made at www.everymothercounts.org/products/donate.

For more from Liv Tyler and Gap’s new film Mama Said, pick up the latest issue of PEOPLE, on newsstands Friday.