Ellen Pompeo was understandably cautious when it came to choosing her next role.

After all she’s been playing beloved Meredith Grey for 20 years on television’s longest-running, prime-time medical drama, Grey’s Anatomy. And while she hasn’t scrubbed out of the show for good (she’s still appearing in a handful of episodes each season), Pompeo is focused on her future.

Now the actress is taking a dramatic leap by starring in Hulu’s new limited series Good American Family (premiering March 19), which takes on the twisted, true-crime story of Natalia Grace. Told from multiple points of view, the show revolves around a Midwestern couple who adopt a Ukrainian child with a rare form of dwarfism. In time they become suspicious that she’s actually an adult and their lives are in danger.

“It was like, ‘Wow, this is intense. How would we pull this off?’” Pompeo tells PEOPLE in this week’s cover story. “And I said, like I say often, ‘This isn’t for me.’ And then everyone around me convinces me that this is something you definitely should take seriously and you should do.”

While the role is a huge departure from her Grey’s character, Pompeo drew upon her own life experience. “I think all mothers have the intention to love their children endlessly and to do everything in their power to give their children the best chance,” says the actress. “I have three children of my own, so a mother’s love and passion was where I started from.”

Pompeo — who’s mom to Stella Luna, 15, Sienna May, 10, and Eli Christopher, 8, with her husband, sportswear executive Chris Ivery, 57 — says she became even more bolstered after meeting actress Imogen Faith Reid, who had been cast as Natalia. “We probably had a two or three-hour Zoom, and we just really hit it off,” she recalls. “And I thought, ‘This is how we pull it off — with her.’ And I wasn’t wrong. She delivers, for sure.”

Although Pompeo did not meet Barnett, her research included reading parenting books and police reports before production began. She admits the story lent to times on set that were especially challenging. “I mean, so much of acting is not only just emotion, but it’s physicality. You have to tie the two things together,” she explains. “And you have to work yourself up, you have to get yourself in a state to be able to deliver certain lines and a truthful performance. It’s hard, but you have to go to dark places in your mind and make yourself uncomfortable. Just the very idea of some things I had to do and say were so tough.”

The actress, who also executive-produced the show with her production company Calamity Jane, says her years on Grey’s and working with creator Shonda Rhimes have guided her toward the projects she wants to develop — and how she wants to bring them to life.

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“Obviously I have a fantastic legacy working with Shonda, and she changed the television game forever, for the better. So I have learned from the best,” she says. “One of the things I’ve always been mindful of and has always been our intention is to tell inclusive stories and to tell all kinds of stories about all kinds of people.”

Pompeo says Good American Family, which also stars The Morning Show‘s Mark Duplass, does exactly that. “We have been able to show and shine a light on how we as human beings look at people, how we judge them, why we judge them, what preconceived notions we have of people based on what they look like or how they may sound,” she explains. “And sometimes that’s for the better and sometimes it’s not. Sometimes it’s a defense mechanism, we think we’re keeping ourselves safe. But at the end of the day, less judgment and more acceptance would do us all so much good.”

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From behind the camera to in front of it, “we walked the walk. And we were mindful and thoughtful and had so many different types of people help us make this show, so many different perspectives, points of view,” Pompeo says of the limited series. “And so much of it was something that you don’t get to do in our job so much. It’s like, we’re making a show and this is how we have to do it, and we have to have these people. And everyone has their ideas. We really were so intentional and thoughtful, and everybody felt supported and represented. There’s not a lot of opportunities to do that, and I’m really proud of this show for that.”

Good American Family premieres March 19 on Hulu.