Melissa McCarthy and Octavia Spencer on Their 25-Year Friendship That Only Got Stronger on 'Thunder Force'

Octavia Spencer was a fan of Melissa McCarthy's long before Bridesmaids, Mike and Molly and The Heat.

In the 1990s, McCarthy and future husband Ben Falcone performed with the L.A. comedy troupe The Groundlings, and Spencer regularly caught their act.

"When I first moved to town, I used to go to The Groundlings to watch them," she says in the new issue of PEOPLE, now on stands.

The three became close friends, and that bond has only deepened over time. Yet despite that, McCarthy and Spencer never had a chance to work together—until their latest project, the action-comedy Thunder Force, out now on Netflix.

It was Falcone's idea to pair the two as superheroes, and he got no resistance from either. "Ben got out half a sentence," McCarthy says in this week's PEOPLE. "He said, 'I'm writing this thing for you and Octavia where you're both—' I was like, 'Done! You don't have to finish it. Are we crocodiles? Okay. Are we bounty hunters?' I was like, 'Whatever. We could be crocodile bounty hunters and I'd be like, 'Yeah, okay.' Which, by the way, Octavia, I would like us to play crocodile bounty hunters."

Spencer, laughing, responds, "I'm in! Well it was very easy. Ben called me up and said, 'Hey, I'm writing a superhero script for you and Melissa.' I'm like, 'Okay, tell me where to show up buddy.'"

It was worth the long wait. "I got her to myself for three months," says McCarthy. "That was almost more exciting than even getting to work with her!" Adds Spencer, "It was a dream come true."

Each has watched the other's career flourish — Spencer won an Oscar in 2012 for her standout performance in The Help, the same year McCarthy broke through with her scene-stealing work in Bridesmaids. And during that time their friendship has only matured.

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"I knew her before she had kids," says Spencer. "And I know her as a mom. She's raising two amazing young women and they have her as a role model. That's one of my favorite things about her. I mean, aside from all of my other favorite things. I just love seeing her with Georgie and Viv."

McCarthy says, "My girls have not known a minute of their lives without Octavia. You come with the package. In some ways, she's not changed one bit. Her moral compass is no different from the day I met her. Her kindness is no different. She uses her talents and resources for good."

After seeing all of Spencer's work, which does McCarthy like most? Self Made, the Madam C.J. Walker story, about the first Black female millionaire in America. (Spencer was nominated for Emmy for her portrayal).

"I loved her getting to tell the Madam C.J. Walker story, because that is what I know. First of all, I love that character. I love her story. And that to me is perfectly Octavia that she took that story that needs to have the light shined on it."

And Spencer's favorite McCarthy role? Can You Ever Forgive Me.

"I remember watching it and saying, 'Oh my God,'" says Spencer. "She got to show so many layers and she made us root for this, this counterfeit artist."