Jason Reitman almost had no choice but to become a filmmaker. His father, Ivan, produced some of the most beloved American comedies of the last several decades, including everything from the original Ghostbusters in the late ‘80s to I Love You, Man, 20 years later. Though he inherited a legacy, the younger Reitman has developed his own style, becoming known for relatable and touching comedic dramas like Up in the Air and Thank You for Smoking that tend to sneak up on audiences by infusing seemingly lighter topics with real emotion.

Jason Reitman’s reputation has been built in part through an ongoing collaboration with writer Diablo Cody, who penned Reitman’s Juno (2007), Young Adult (2012), and now, Tully. Like Young AdultTully stars Charlize Theron, this time as a spread-too-thin mother of three who is barely hanging on to sanity until she finds a surprising savior in a free-spirited young nanny, the titular Tully, played by Mackenzie Davis. Cody has also thrown a wrench into the script that will leave you wanting to go straight back to the theater and watch it again.

In advance of Tully’s theatrical premiere, Jason Reitman got on stage with fellow filmmaker Tamara Jenkins (Savages, Slums of Beverly Hills)  at the Tribeca Film Festival to share filmmaking lessons passed down from his father and some he himself has picked up along the way. Our top takeaways from the conversation are below.

Not everyone can write as fast as Diablo—and that’s ok

Reitman calls Diablo Cody a “pure writer,” telling Jenkins that, “This is gonna frustrate the shit out of you, what I'm about to say.” He went on to recall that, for Tully, Cody gave him a two-sentence description of a movie. He encouraged her to write it, and six weeks later, he had a script.

“I got an email, the script was attached, and that was the shooting draft. I mean, that's the movie that we went and made,” he said. “She's a pure writer in that she does not index card, she does not do a treatment, she just knows what the first scene is, and then she just starts writing. And she kind of walks into the woods and walks out the other side.”

Reitman admitted how unusual this is—it took him seven years to write Up in the Air, for example. How does Cody do it? Reitman surmises, “She just needs to get it out of her system. She needs to write every day.”

"I'm amazed by the amount of parents who have dropped their phones on their baby's faces."

Personalize your script research

One thing that stands out in Reitman and Cody’s collaborations is their authenticity. In a story about parenthood, they could naturally pull from their own experiences—Cody is a mother of three, Theron a mother of two, and Reitman a father—but they also put together a research questionnaire for new mothers.

Reitman recalled telling participants, "’Whatever you're willing to share with us, we'd love to know any real details from being a new parent, from right now.’ And we went to the cast and crew and said the same thing: ‘Please, be open with us, if you can think of anything…’”

By asking broad questions, they received specific answers that enhanced the “rich details in the movie.” Apparently, one of the most memorable vignettes came from a props assistant. The questionnaires generated funny moments (“I'm amazed by the amount of parents who have dropped their phones on their baby's faces; that is apparently quite widespread”), but also quite serious themes.

Reitman shared, “What was clear was that they had not told any of this to anybody. They talked about their marriages going quiet. They talked about their sex lives, they talked about how their younger self had started to feel like a different human being, how they didn't know where they were in their timeline anymore.” These themes helped develop the key relationship of the film, between Theron and Davis’ characters.

TullyMackenzie Davis and Charlize Theron in 'Tully'

Know which kind of actor you’re working with

Of course, no matter how truthful your script is, the movie’s believability depends on the performances. In describing his repeated work with Charlize Theron, Reitman insisted that finding chemistry between actors is of primary importance for directors. “I mean, that's almost our entire job,” he said, “is how to know that and knowing how to pair people together.” In order to do that you need to understand what kind of actors they are.

For him, actors fall into two general categories: “There's human puppets, who are very good at puppeteering themselves, and if you can describe, "I need you to come across like that," then they can puppeteer themselves to appear that way, and they can be very good at that. There are great actors who can do that.” The second type of actors “are lost in it, and they just actually feel what their character's feeling.”

According to Reitman, Theron is one of two actors he’s ever met who falls into both categories. “She's 100% aware of everything that's happening around her—crew-wise, camera-wise, acting-wise, on set, in the scene—but simultaneously knows exactly how to get in touch and be one whole”.

Tamara Jenkins likened this to working with Philip Hoffman, whom she directed in Savages, recalling “I always thought, ‘Oh, he's got the third eye.’ So he's inside the movie and inside the part, but he's also kind of has a directorial sense of where camera is, what's happening. But he's so inside of it, he doesn't eat between takes.”

Mackenzie Davis, on the other hand, “is completely unaware of everything that's happening around her. It’s like, ‘Mackenzie, you need to move a step to your left.’ ‘Why?’ ‘You're standing right in front of the camera, like, right in front of the camera.’ She's just kinda lost in the scene, which has its own kind of beauty to it.”

"Once I started applying that to my work or any movie I've ever seen, it hit me. The ones who got that right, the movie succeeded."

Though their working styles differ, Reitman said that Theron and Davis are “both smart, both thoughtful, and all of our conversations are the good ones. He went on to share that, as a director, “you crave those smart conversations, and you fear the dumb ones. You fear working with an actor who only wants to talk about the dumb stuff, and you crave the actors who, every morning, the conversation is, "How do we make this more real? What is the one thing in the script that doesn't feel right now? How do we get rid of that and how do we get further in detail?’”

It’s a large part of your job as director to understand how your actors work and how they respond to their surroundings in order to get the most authentic performances out of them.

Focus on the plot, not the ‘location’

Reitman shared that one of the major lessons he learned from this father is to know the difference between your location and your plot. He recalled a time when the senior Reitman invited him over to watch the show 24. The young director asked his father "What is it about this show that makes it so good? I mean, there's lots of shows about terrorism."

Ivan Reitman responded, "This isn't a show about terrorism. Terrorism is a location. This is a show about a man trying to keep his family together."

The truth of this insight made an impression on Jason Reitman, “And once I started applying that to my work or any movie I've ever seen, it hit me. The ones who got that right, the movie succeeded, and the ones who got it wrong, you know you're watching a movie that's about the location, and not about the plot.”

Aaron-Eckhart-in-Thank-You-For-SmokingAaron Eckhart in Jason Reitman's 'Thank You For Smoking'

Your barometer for comedy will never be as good as your barometer for truth

Perhaps Ivan Reitman’s most enduring piece of advice to his son was imparted a couple days before Jason Reitman started shooting Thank You for Smoking. Jason shared that his father said, "Remember, it's not your job to be funny. Your barometer for comedy will never be as good as your barometer for truth, so when you're on set, never ask yourself it's funny, never ask yourself it's scary or dramatic, you won't know. But you will know if it's truthful. You will know if it's honest.”

Ivan Reitman continued, “So, everything—dialogue, clothes, hair, how someone walks in, sitting or standing, where the conversation should end or start—Ask yourself, do you believe that?"

Jason Reitman has certainly taken that advice to heart, admitting, “When I'm on set on a film like this, that's frankly what's going through my head.”

Great collaborations, personalized research, a keen sense of acting process, and a commitment to truth have all contributed to Jason Reitman’s impressive and audience-pleasing body of work.

Featured image of Charlize Theron in 'Tully,' which hits U.S. theaters May 4.