Dakota Johnson and Sean Penn share a cab and life-changing conversation in 'Daddio'

"She said, 'What do you think about my dear old friend Mr. Sean Penn?'" Hall says of Johnson's suggestion that they approach her neighbor, the one with two best actor Oscars. "I was like, 'Are you kidding me?' Again, I said we would be so lucky."

Penn read the script and within 48 hours was on a Zoom with Hall to say he would do the part. Soon, she and Johnson were at Penn's house, doing what she'd always done in the theater, doing table reads, allowing the two actors to ask questions about their roles and dialogue, making clear how the story would unfold.

"After we did table work, we got it up on its feet," Hall says. "Sean took a handheld mirror and duct-taped, I think to a broom and chair. Because if you think about it, they're never actually really looking at each other. They can connect by way of the rearview, so I think he wanted to get a sense of what is that even going to feel like."

Life in the cab

For the actors, filming almost the entire movie on a soundstage, with Penn behind the steering wheel of a cab, and Johnson in the back seat, was an exciting challenge.

"I think it added so much tension and mystery to when you're working with someone and you can only see their eyes in the mirror," Johnson says. "It gives so much to your own performance and to your own experience in that scene.

"It just felt different and magical," she says "It felt like a very quiet — like physically quiet but emotionally loud experience," she says.

"I like when I can talk to people without worrying about whether I have something between my teeth," Penn says, grinning with perfectly clean teeth. "So it was good."

Hall had considered shooting the cab scenes in an old-school way, with cameras fixed inside and outside as it was pulled by a trailer through the city, but the vagaries of traffic, weather and time — the shoot was only 16 days — ruled that out. Using green or blue screens to create the scenes outside the cab would have been far beyond the indie film's modest budget.

So she and director of photography Phedon Papamichael adapted the technology used on "The Mandalorian" for their earthbound drama, encircling the cab on the soundstage with panels of LED screens onto which the world outside could be seen in real-time as the cab and its passengers moved through the city.

"I never went up to the front of the cab except for when I leaned up in the movie," Johnson said of her two weeks in the backseat of the cab. "It felt like Sean's space and my space. I loved it. Every day to go into work and like sneak behind the screens and just pop into our positions and have our own little worlds? It was great."

Penn was equally happy with his domain behind the wheel; he only shifted during a section midway through the film when an accident on the highway forced the cab to stop until it was cleared.

"I communicate better at home, and the cab is my home," he says, laughing. "Somebody comes into my home is how I'm feeling about it. And I had just a delightful guest."

Forever changes

As the cab slips through the Midtown Tunnel from Queens into Manhattan, the conversation deepens. Clark pushes Girlie to confront difficult aspects of her life. She, in turn, demands the same from him.

As they near her Hell's Kitchen home, Girlie admits her deepest secret, an event that occurred on her visit with her half-sister in Oklahoma, which she has barely even admitted to herself. Both she and Clark reach the destination with more vulnerability and honesty than when they'd pulled away from the terminal at JFK.

"I think it affects her profoundly," Johnson says. "I think her life changes after that cab ride. Maybe not immediately. I don't know what she chooses. You know, people are interesting. But I think the discoveries and the realizations that Girlie has, she can't unknow them after that. Even the discoveries that Clark has, he can't unknow them.

"It felt like she has more compassion for herself in her life from getting into the cab to getting out of the cab," she says. "And that is something that I think is a profound gift."

And for Clark? "Well, I think I don't want to tell you," Penn says with a smile when asked how his character is changed that night. "It was so interesting listening to it and I was going through that. I think an audience will have their own version of that."

But would he agree that Clark is changed?

"I think he really hopes so," Penn says, and smiles again.