Let's Have Kids! Filmmakers Share Their Most Surprising Casting Stories In New Karen Gillan Comedy

Published Nov 3, 2026, 11:31 AM EST

As a graduate of Columbia University in New York City, Tatiana studied theater and comparative literature. She has been passionate about all manner of storytelling from Jane Austen adaptations to anime. Aside from writing for Screen Rant, she co-hosts podcasts: The Flash Podcast and Ladies With Gumption.

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Let's Have Kids! answers the burning question of how friends stay together even as life pulls them in opposite directions, and filmmakers Adam Sztykiel and Ellie Knaus pulled out all the stops to tackle it as honestly (and hilariously) as possible. The movie follows two literally lifelong best friends, Emma (Karen Gillan) and Phoebe (Zoë Chao), who make a snap decision to have kids simultaneously. But when only one of them winds up pregnant, an emotional crisis ensues that tests them, their spouses, and the rest of their interconnected world.

Let's Have Kids! was written by real-life partners Sztykiel and Knaus, who combined their personal observations and cinematic know-how to craft a humorous and heartfelt tale of friendships surviving big life changes. Sztykiel also helmed the movie, which served as his feature film directorial debut. Alongside Gillan and Chao, the comedy boasts a top-notch cast that includes Sam Richardson, Max Greenfield, KJ Apa, Mary Steenburgen, Ed Begley Jr., Lilly Singh, and Luke Macfarlane.

ScreenRant interviewed the minds behind Let's Have Kids! to uncover delightful casting stories that brought the comedy's uproariously funny ensemble together. Knaus and Sztykiel also went behind the scenes of their script development process and shared how Knaus' Atomic Moms podcast laid some of the foundation for the pre-parenting experiences in the film.

The Biggest Casting Surprises Of Let's Have Kids! Explained

ScreenRant: The casting in this movie is top-notch. Did you guys have Karen and Zoë in mind when writing, and how did they come aboard? Was there anyone in the cast who was an exciting surprise?

Adam Sztykiel: This is the most specific one: Sam Richardson, whom I love and who is also from Detroit. He was just one of those people that I wanted to do something with.

When we wrote it, the character's name was Sam, and I was like, "This is Sam Richardson. And by the grace of God... Zoe Chao was very close with him, so after she had been cast, she was like, "I'm seeing Sam tonight," and we were like, "Just do whatever you gotta do..." When Sam came on, I asked, "Do you want us to change the name?" and he was like, "Yeah, I'd love to not literally play myself." That's why he's Ben in the movie!

But that's the most extreme example. In large part, we got everyone we wanted. To see someone like Mary Steenburgen, whom we have loved forever? Ellie's entire life, she has been told that she sounds like Mary Steenburgen, so it was incredibly special for us to have her in this movie.

Ellie Knaus: The biggest surprise, because we started writing this in 2019, is that when we shot it in 2024, our daughters were in it [playing KJ Apa's children].

ScreenRant: Speaking of KJ Apa, I never would have thought it, but he makes the perfect sibling for Karen Gillan. How did he come to mind?

Adam Sztykiel: His character, Rob, comes in real hot with a lot of strong opinions. He's a big character, so we really were thinking, "Who is that guy?"

There was a brief moment in my life when I was going to direct a movie adaptation of Wonder Twins, a Wonder Twins movie. I know, wouldn't that be something the world needs? We had gotten as far as casting the movie, and he was going to be in it. Even though he was known for Riverdale and dramatic stuff, because we'd read a bunch of scenes together, I knew how funny he was. I got to know him personally, and he's a buddy, so I was just like, "I feel like the world doesn't know how funny he is."

The funniest part of this casting is that our producer Becky only knew him from Riverdale, where he has red hair. So, she was like, "Oh, my God, it's perfect!" I was like, "Well, that's not actually the color of his hair... But I agree! It's perfect." We reached out to him, and thankfully he said yes, because he crushes it. He's so funny in the movie.

ScreenRant: Was the ending always the same, or did it change at all in the process? Did you ever consider making Emma actually unable to conceive, or end it without her potentially being pregnant?

Ellie Knaus: Yeah. I like to examine all sides of an experience, and I do think that there is a beautiful ending where the two lines don't show up, and that's okay too. And it's kept reminding me that it's a comedy.

Adam Sztykiel: I would say that there was some struggle just because I think it's in a movie where we were striving for authenticity, and where we were really trying to be true and honest to everyone's experiences within the movie. That is the moment where I feel like, "This is a movie. I have put my characters through a challenging emotional arc."

If you want the real nuts and bolts of how I thought about it, it was something that Emma initiated at the beginning of the movie. The character work has occurred; she has come to terms with the fact that her friendship, while different with Phoebe, is no less special or meaningful. It's just different now. As a result, I think it's okay.

In a comedic and weird way, she's come to a place where she's like, "This is actually pretty sweet. I kind of like it." I also like the joke of, "Be careful what you wish for". But I love movies, and I'm a populist, so I've got to leave room for the sequel.

Let's Have Kids! Has Its Roots In Real-Life Experiences

ScreenRant: The two of you have obviously collaborated before, in both your personal and professional lives. But what was the initial spark that led to this film?

Adam Sztykiel: When we started writing it, we had our kids. Friends of ours had had kids, and my sisters both had kids. I noticed that there were people - like my sisters - who got pregnant more or less at the same time. There was even an instance where I said it to my friend, "You know your wife and her friend collaborated, right?" He was like, "No, no, that's just a crazy coincidence." That's where it started, just as a funny idea.

I was also really watching Ellie and her community of mom friends, and how they really provided a support system. As hard as I would try, I couldn't do it because I'm a man. I don't have that experience, and I don't know what it's like to be a woman - let alone a mother. Witnessing that was really the special heart of it. And in the beginning, it's very hard as the partner, because you want to be there, and you always want to be like, "I got this," and "I can be there." But once I let go of that and realized how amazing it is that she has this community of people that can help her through things that I can't, that's really where the heart of the movie came from.

Ellie Knaus: We had some family members who had children, but in our Los Angeles community, we didn't have friends with babies yet. I think part of what was exciting about making this film was remembering that feeling of, "Wait, if I get pregnant and none of my friends are pregnant, there's gonna be FOMO. I'm gonna be in a totally different world than them." We did get pregnant first, and my girlfriends were so sweet in throwing our baby shower. One perk of being the first is that your friends still have time to help.

Over the years, everyone added their families into the mix, and our friendships have evolved. I met one of my core group of girlfriends in 2008, and we're all still very close. It's wild to see everyone's evolution, and there are times when we lose touch for a bit because of work or family, but it's really special that we can come back together. And this film has been this incredible opportunity for that to happen.

We've had some audience members at some screenings say, "I reached out to my girlfriend after this film." I think that's the coolest part, because whether you have children or not, friendship gets many of us through really difficult times, and that means everything to me.

Adam Sztykiel: When you sit down to write a movie, you have the whole journey in your head. There's a scene in the movie where Karen's character, Emma, says, "You're friends with the people you go to school with, the people you work with, and the people that you have kids with." That's her big fear, and I certainly went through that.

When you have kids, you can't go out 'til 1 in the morning anymore, and you do start to drift away a little bit from those other groups. But you also make these amazing new friends. And the resolution of the film is that all those friendships still [have value]. It's no better or no worse. It's just different, and my life is fuller because of all the new people that I've met as a result of being a parent. That's the journey that these characters go on over the course of the movie.

ScreenRant: Ellie, I know you had the Atomic Moms podcast, where lots of stories have been shared about parenting. How did that experience influence your approach to Let's Have Kids!, especially in toeing the line between heartfelt and hilarious?

Ellie Knaus: Oh, what a lovely question! I think that's why I was invited into this process. Adam, over many years, had been watching me record and edit and do this thing I cared so deeply about - and I feel like I gave myself a little PhD program in parenting. I never came at it as an expert. I'd interview the experts, and I was a guinea pig. But I was always curious about everyone's unique experiences.

When Adam asked me, I was a little nervous because I care so much about the parenting community. It's a comedy, but I wanted to make sure that it felt good for everyone, because it is such a tender time in life. I was so proud watching the film because I feel like we did thread that needle. There's a lot of stuff to laugh about, but there's also a tenderness.

What I'm really proud of is that the podcast gave voice to a lot of these experiences, and this film is able to bring it visually to the screen in a way that I have not seen before. Like the birth scene, like the postpartum scene. These are things that we rarely show, and that is really meaningful for me and for the women that have seen it, that have shared with me. Like just to see any glimpse of this on screen mirrored back to us, it feels special.

Let's Have Kids! is now streaming on Prime Video and available to own on Digital.