In Juno, Ellen Page’s pregnant teen was forced to grow up too quickly. In Young Adult, Charlize Theron’s divorced author refused to grow up. And in Tully, a soon-to-be mother of three just wants the ease and simplicity of her youth back. All three Diablo Cody and Jason Reitman collaborations explore women struggling with who to be at different stages of life, but their latest is easily the most personal.

In Tully, Theron reunites with her Young Adult screenwriter and director to play Marlo, a pregnant mother with her third child on the way. As exciting as a newborn may sound, for Marlo, this baby wasn’t exactly planned, and Marlo has enough on her plate as is: her son is on the brink of getting kicked out of kindergarten, her daughter is at that age of budding self-doubt, and her husband (Ron Livingston) is too occupied by Call of Duty to lend a hand. Not to mention, her figure isn’t what it used to be – “Mom, what’s wrong with your body,” her daughter nearly shouts at the breakfast table – her sex life: nonexistent, and she’s drowning in the depths of postpartum depression. Then a miracle occurs when Mackenzie Davis’ Tully knocks on the door, a night nurse who also happens to be the hip caretaker of every mom’s dreams.

A story as honest as this could only come from real-life, and it did. Cody told me over the phone last week that the idea for Tully came to her after she had her third child. “I was really overwhelmed and just feeling this anxiety that I’d never felt before,” she said. “I just knew that the one thing in life that I longed for more than anything was for someone to take care of me at that moment. I just thought, if I could envision the perfect caretaker, who would it be?” Thus, the third Cody and Reitman film was born.

The screenwriter told me about working with Reitman and Theron again, the lack of gritty movies about motherhood, and what inspired the character of Tully. She also revealed what happened with that Barbie screenplay.

I was thinking about this film in relation to Juno and Young Adult and how it feels like the end of a loose trilogy in a sense. These three stories about women at different stages in their lives and the expectations often placed on women at those ages. Did you see this film in conversation with those two?

I do now. [Laughs] I have to say going into it, I didn’t think of it. Like you say, I do feel like it’s about, the movies represent a different stage of life for women, but also for Jason and myself, weirdly. The tone of the movie sort of reflects where we were at in our lives respectively when the movies were made. I don’t know if it sort of came out of my subconscious or what, but it does feel like they’re of a piece.

Where did the idea of Tully originate for you?

I was going through a pretty challenging time in my life. I had just had my third child and I really don’t want to sound annoying, like self-pitying breeder because I love being a mom and I understand that that was a decision I made. But I don’t think I was entirely prepared for what it would be like with two boys at the under the age of 5. And work. [Laughs]

I was really overwhelmed and just feeling this anxiety that I’d never felt before. Jason had called me into his office just to chat about something. It wasn’t even a formal meeting. And I was in there and he said, “I want to do another movie. What should we do?” Which is a conversation that we have a lot. And I said I think I have something and I just started pitching Tully, the whole thing, straight to through the end. And he said, “I want to do this and we should do this with Charlize.” And I said great. I’m going to go write it. Strange thing.

The story just kind of announced itself. I don’t even know how to explain it. It definitely wasn’t something I sat down and totally outlined for weeks. I just knew that the one thing in life that I longed for more than anything was for someone to take care of me at that moment. And that is where Tully came from.

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In the film, there’s this idea that motherhood can mean giving up your own life for the life you bring into the world, which is something we really don’t see explored in movies. You portray it with a real naturalness here.

Thank you. It was important for me to tell this story because I’ve seen other representations of motherhood, but they tend to be humorous. Mommy needs vodka. The coffee mug slogan. And I thought no one has really gotten gritty with it. Because there’s a side of it that’s dark. And it used to be enough to be just a good caretaker and now it’s that you need to be a good caretaker, you also need to be fit, hot, successful, etc. And it’s a lot.

The film strikes that balance between comedy and the seriousness of postpartum depression, but writing that, what was that like? Did you find yourself having to pull back if it got too dark? Or if things became too comedic?

I just followed my own emotions. I just kind of went there, and if I was feeling dark, which I was on many days, that’s where I went. I could never write something that was purely dramatic. There’s always going to be a dark comedic bend to it. I can’t stay away from that, that was where the humor came from. I was also thinking about Jason as a director and how Charlize would perform it. I don’t think I’ve ever done that before, having the entire creative team in mind while I was writing. So that was fun.

So you wrote this with Charlize in mind?

I didn’t know for a fact that she would do it, but I did know that her and Jason wanted to collaborate again. I would certainly think about it. You can’t do any better than her. She is so brave. She is so brilliant. There is nobody like her. I loved making Young Adult with her so much, I had my fingers crossed.

What was it like being back with her and Jason again? Do you and Jason have a shorthand when working together? 

Jason and I definitely do and Jason and Charlize definitely do. Charlize and I don’t get to interact as much because I’m not directing her performance. But she and I obviously talked about the script. I think she’s an amazing person and I loved hanging out with her because she’s so cool.

The character of Tully is so wonderful and strange. She’s like a hippie Mary Poppins.

Thank you!

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Where did she come from within you, this kind of alien character who is the perfect cool girl?

I don’t want to give too much about the movie away but the qualities that she possesses were really important because, you know? How do I put this – Tully is meant to be the essence of youth and energy and curiosity. One of my favorite things about her is when she’ll bust into the house and just start raiding the fridge because she’s voracious and unself-conscious. It’s the only way you can really be when you’re young, or at least only I could when I was young.

It’s just something that you get away from as you get older and it becomes okay. Exercise self-discipline, don’t go looking for trouble, come home by a certain hour, get a good night’s sleep, get a lot of antacids in your diet. It becomes about rules and rigor, so when you’re young its like, f–k it. I’ll smoke a cigarette. I don’t care if its gonna kill me. [Laughs] It’s that recklessness that I think goes away for most people.

Like you said, it’s really hard to talk about this movie without giving anything away. But if you don't mind talking about it without spoilers, I do want to ask you about the twist at the end. Was that always in mind or did that evolve as you wrote the script?

Oh yes, that was always the point of the movie. That was always the heart of the movie. That was there before anything else. I don’t know if – I guess there’s a scenario where the movie would work without it, but for me that was the whole gist. How do we access who we once were while being responsible and evolving as adults? Can we use that access to improve ourselves? Is there a way that we reach back into the past and regain some of the positive from who we once were?

I’m a big fan of The United States of Tara, which I wish had lasted longer –

Thank you, me too.

I couldn't help but notice some similar threads between it and Tully, about how far trauma or depression can push characters struggling to cope. Did you see those two as connected?

This project is spiritually connected to The United States of Tara in many ways. That show was about a woman losing her alters, her other personalities trying to get through life. That was a coping mechanism. She would disassociate and rely on these other sort of souls and it varied on what sort of situation she was in. That kind of was born out of the same frustration for me. And I wasn’t even a mom at that point when I started writing United States of Tara, but I could already sense this pressure to be a lot of different things at once. I suddenly had a really high-pressure job and it was like, yeah we need you to be responsible, we need you to be creative, we need you to produce and be productive, but at the same time we also want you to be this fun, creative random rebellious lady that we found in the Midwest. I just felt, who am I? Who am I supposed to be? It’s just gotten harder from there Oliver! Just kidding, but yeah.

I want to ask about your Barbie screenplay, which you worked on a while ago. I know they brought on writers since your initial draft. Are you still involved at all? Do you know if they kept any of your original ideas?

Dude, I never even produced an initial draft. I failed so hard at that project. I was literally incapable of writing a Barbie script. God knows I tried.

Was there a reason that you couldn’t do it?

To be honest, the timeline coincided with my writing Tully. I was really overwhelmed at the time, and I think I was really only capable of reaching in and pulling out something super personal. Look, I think the idea of a Barbie movie is super f—ing cool and I hope something goes in there and kills it. And I mean kills it in a positive way. I hope it’s a great movie is what I’m saying! [Laughs] Which is why I initially signed on to do it, which I think is a cool idea, especially now. But for whatever reason, I’ve always had trouble, I’ve never been great at adaptations. I think when it comes down to it, I’m pretty much an original screenplay person.

It just has to come from somewhere personal for you?

Yeah, it kind of does. I mean there’s exceptions. I just wrote this musical with Alannis Morrisette where her songs are the inspiration. But again, that was an original story they let me create.

Tully opens on May 4.