"I have a sense of safety and comfort when I'm around them," the Firefly Lane star tells PEOPLE
katherine heigl
Credit: NBC/Getty

Friendship is a powerful thing — as Katherine Heigl knows well.

In her new show, Netflix's Firefly Lane, out Wednesday, Heigl plays Tully Hart, a fearless TV host, throughout her 20s, 30s and 40s as she journeys through life with her best friend, Kate Mularkey (Sarah Chalke). Their sisterhood through the years is at the center of the drama, which is based on the novel by Kristin Hannah.

A key element of Heigl's life, too, is her longtime friend group, which she affectionately calls her "Sacred Six," whom she says help to empower her on good days and bad.

"I have a sense of safety and comfort when I'm around them," Heigl, 42, says in this week's issue of PEOPLE. "Their constant-ness has given me a sense of self-love and self-worth."

Much like Tully and Kate on her show, Heigl's group first came together when they were in middle school and high school.

Katherine Heigl and Sarah Chalke in Firefly Lane

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"Together we navigated those incredibly tumultuous and hormone-driven years, and then as we got into our early 20s, we lost touch," Heigl says. "A high school reunion brought us back together, and since then we have maintained the connection. Having that history makes this bond between us so powerful. I don't feel like I have to be anything other than just who I am — and they love me regardless."

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However, amid the pandemic, the Emmy winner and mother of three is still spending the bulk of her time with her family, including her husband, musician Josh Kelley, at their home in Utah. The couple shares son Joshua, 4, and daughters Adalaide, 8, and Naleigh, 12.

Josh Kelley and Katherine Heigl
Josh Kelley and Katherine Heigl
| Credit: Mike Coppola/WireImage

"In the 15 years we've been together or the 13 years we've been married, we have never spent this amount of time together," Heigl says of Kelley, 41. "This has been an interesting experiment in romance, that's for sure. "

It helps that Kelley is good with his hands, though.

"Josh built this little shed in the backyard for us to go and hide, and it's been a real lifesaver," Heigl says. "We leave the kids, and we try to talk about each other and remember we're not just parents."

While Heigl admits Kelley "can be really annoying and I can be really annoying," she also says without hesitation that she still wants "to do life with my best friend."

Firefly Lane is streaming now on Netflix.