The film, which also stars Shia LaBeouf, Ellen Burstyn, and Benny Safdie, premiered at the Venice Film Festival and will screen next in Toronto.

When it came to her portrayal of a grieving mother grappling with unimaginable tragedy in Pieces of a Woman, Vanessa Kirby sought one thing above all: authenticity.

Executive-produced by Martin Scorsese and directed by Kornél Mundruczó, with a screenplay by Kata Wéber, the film follows Martha (Kirby) and Sean (Shia LaBeouf), a couple reeling — in very different ways — from the grief of losing their newborn daughter during a home birth. It doesn't shy away from the often unglamorous realities of childbearing, or womanhood, or grief, and for Kirby, that was an integral part of her performance.

"It was really important for me to try to portray a real woman, not a movie version of this where the actress is made-up the very next day. I just wanted there to be no vanities through all of it in any way," the Emmy-nominated The Crown alum tells EW. "I wanted to feel the authenticity of that experience, because to not do that would be betraying the experience that these women have had."

Pieces of a Woman had its world premiere over the weekend in Venice, where Kirby earned career-best reviews and was met with early Oscar buzz. Now the film heads to Toronto for its North American debut, and where buyers will no doubt be circling. (It's still seeking distribution.)

Ahead of its Canadian bow, Kirby spoke with EW about all the ways she prepared for the role (including watching a birth in person), the challenge of shooting the nearly 30-minute birthing sequence in one take, and how the film hits a bit differently during a pandemic.

ENTERTAINMENT WEEKLY: What about this character really spoke to you and made you want to tackle this part?

VANESSA KIRBY: I guess the challenge of it, really. Also, I knew that it was a kind of an experience or a subject matter that hasn't been explored on film a lot. I know for the women that I spoke to and spent time with that had been through this, I don't think they've seen their experience on screen in this way before. I think we all felt like there was a responsibility here for anyone that's been close to someone who's gone through this or have gone through it themselves, as a woman, but as partner, as a man, too. It was that as well as the challenge and how demanding it was to truly kind of try and represent grief in that way. It made me think of Three Colors: Blue, which is one of my favorites films, and it felt like a companion to that somehow.

The birth sequence, which is nearly 30 minutes long, was one continuous take. What was your reaction when you realized you'd be doing that?

We kind of all made the decision together, really, and I actually was truly excited about it because I came from theater, which is kind of uninterrupted. So the idea of doing a 30-minute take with no cuts was really kind of exhilarating to me. It required us to kind of freefall. Also, as a company, we started with that as our first two days of filming — we did four takes [of the scene] the first day, two the second — and it required all of us to kind of jump off a cliff, really, and freefall altogether, including the amazing [cinematographer] Benjamin Loeb — he was the MVP — he just held his camera the whole time. He literally followed us for half an hour capturing different moments of the process. It just honestly felt like we took a jet and we jumped off. It was deeply bonding. We felt like we'd been to war together.

How do you prepare for something like that?

Well, I'd never given birth myself and I knew I had to try and portray it as authentically as possible, because if you don't believe that [scene], then none of the rest of the movie works. And to do it in one take, I knew that any moment where we didn't believe it would ruin it. And so I started off kind of watching as many different documentaries as possible and nothing quite captured it, that true, lived-in, whole experience.

So then I knew that I was going to have to find people that really, really knew this stuff and could help teach me and I could learn everything about it. I found this amazing obstetrician called Claire Mellon who works at a hospital in North London and went to shadow her and be with the midwives for many days. They were so generous and totally took me under their wing, and showed me everything. Then sort of a miracle happened where, on one of the afternoons, a woman came in and she was 9 cm dilated. So, she was really just about to start pushing. She allowed me to be there in the room with her, and that changed everything for me because I realized the miracle of it, and the terror as well. I could not have acted it without her being so generous. I also found this amazing woman called Elan McAllister, who'd made this documentary called The Business of Being Born, which was about the kind of industry of birth. We ended up flying her over from Portland and she was there with us during the birth and helped sort of devise the dance of the birth. She was unbelievably helpful.

Pieces of a Woman
Credit: Pieces Film, Inc.

The film is incredibly realistic with the details of birth and grief, from Martha's messy hair and her nails to the adult diapers she wears and the leaking breast milk. Was all that in the script, or did you add that in?

No, actually, we added them as we went along. So, the diaper was added because a friend of mine who had several miscarriages, she was like a really high-powered lawyer, and she had to go to work the next day after one of her miscarriages, and she said, "You know, I was at work, I was wearing a diaper and I was doing a big presentation. And I would go to the loo and have blood in my diaper, and I would go back to my computer and carry on, and I couldn't talk to anyone about it, and I couldn't tell my bosses, and I didn't know how to." And it just stayed with me so much because I just thought, God, this is such an unseen struggle, and a private one. I mean, from her experience, she said [it was] a very lonely one. And there were so many different stories from women that I spent time with; I tried to weave all of their individual experiences into the whole thing. So, one day on set, I ordered diapers and was wearing them throughout the film. Some of them you see and some of them you don't. I felt those little things were important because Martha is so restrained, she's pushing down her grief so much and actively not wanting to confront it because it's just too painful, so I wanted little bits here and there to portray it, so the audience would just feel for her.

You finished shooting the film right before the COVID-19 pandemic. Has the pandemic changed how you feel about the film and its themes?

Oh, yes, Kornél talked about this recently. I think there's been much loss during the pandemic. I think people have lost many things. And Kornél said to me that he hopes in some way that the film speaks to people who have lost something and how, although we might never be able to come to terms with it, it's how we live alongside the grief, basically. [The film] is in some ways universal — yes, this is a story of a woman who loses a baby or a family that loses a baby — but I think in many respects, people have lost things, or lost their loved ones as a result of [COVID-19] or other things, and so I hope in some way there's a sort of coming together over collective loss and looking at how do we find our way through it. I think for Martha, she finds her voice at the end. She'll never be the same, but through that process, I think Martha finds parts of herself. I think that's why it's called Pieces of a Woman, because she finds pieces of her that she didn't know that she had, and that's her way through loss and how she begins to come out of it.

This interview has been edited for length and clarity.

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