Brie Larson doesn't even remember filming the most emotionally charged scene in Room. She recalls the adrenaline and the exhaustion, but none of that explains why she woke up the next day with bruises. She pieced together what happened with the help of co-stars who approached her later to ask if she was okay.
On a scale of Point Break-era Keanu to Heath Ledger as the Joker, that's the kind of immersive commitment that borders on treacherous. But it's paying off. The role is a turning point for the 26-year-old after acting for nearly two decades. This awards season she's already won a Golden Globe, a Screen Actors Guild Award and would seem to be one to beat among the best actress Oscar contenders.
If Oscars chatter depends on the heaviest of human drama, Room has plenty to go around.
The movie, directed by Lenny Abrahamson (Frank, What Richard Did), was adapted from Emma Donoghue's 2010 Man Booker Prize finalist inspired by the horrifying case of Elisabeth Fritzl. Held captive by her father for 24 years, Fritzl had seven children while imprisoned in a hidden corridor beneath her family's Austrian home.
In Room, Larson plays Joy, a 24-year-old who was kidnapped at 17 by a man she calls Old Nick (Sean Bridgers) and has been locked in a shed ever since. Her only company is her 5-year-old son, Jack (Jacob Tremblay), who believes that the interior of their tiny home comprises the entire universe. Every object goes by a proper name, as if it's a friend, and Jack greets them all each day: "Good morning, Table. Good morning, Sink. Good morning, Room." Everything he sees on television, his mother tells him, is just make-believe.
To make a devastating story more appealing, marketing for the movie has made a point of disclosing a major plot point, even if some people consider it a spoiler: Mother and son aren't locked up forever. The trailer shows "Ma" coaching Jack through a harrowing escape that involves rolling the little boy up into a carpet so that he can wiggle out once he's outside of the shed - and beyond the walls of the only world he's ever known. The second half of the movie explores what happens once Joy and Jack are reintegrating into society, which is hardly a fairy tale ending.
But back to the amnesia: The intense scene that Larson doesn't recall filming is when her character, crying hysterically, is released and reunites with her son.
"I was in such an adrenaline rush, and I was running through the snow in socks with just those track pants and a tank top and no bra," she remembered. Abrahamson had told the actors playing police officers to chase after Larson and try to put a coat on her. "And I guess I was fighting them off and hitting them, and then I slipped and fell on the ice, and then, when I went to dive into the police car" - where her young co-star was sitting in the backseat - "I guess I hit my head."
She slept the whole ride home that evening.
Larson's other big star turn last year was Amy Schumer's summer movie Trainwreck. In real life, Larson doesn't seem far off from the entirely grounded, slightly sardonic character she played in the hit dramatic comedy.
In person, she comes off as politely reserved but philosophical and engaged. And she looked, reassuringly, healthier than she did in Room. Dressed in black - skinny pants, a sweater and heels - she leaned forward on a couch with wide eyes and elbows on knees, as if preparing to literally jump into explaining why the movie is like Plato's cave allegory with a bit of mythology thrown in.
Larson spent months preparing for the movie. She talked to nutritionists about the effects of vitamin D deficiency and poor nutrition plus researched what would happen without access to a toothbrush and other basic necessities.
Already lean, Larson went on a fairly restrictive diet of mainly vegetables and protein to build muscle but lose fat. She didn't want to look like she was wasting away, especially since she needed the mental capacity to take on the taxing role.
"I was actually the healthiest I've ever been in preparation for looking the worst I've ever looked," she said with a laugh. "Part of putting on the muscle was I wanted to have that feeling of strength - that mama lion feeling that if (Ma) had spare time in Room, she probably would have been doing push-ups or something to move the energy around; she's constantly carrying her son or wrestling with him or keeping him occupied."
Before filming, she let her typically highlighted hair become a mousy shade and she stopped washing her face and shaving her armpits. The makeup artists on set didn't have much to do beyond staining her teeth and adding some shading under her eyes and along her cheekbones to give the usually radiant actress a tired, sallow appearance.
But the role involved emotional preparation as well, and Larson used her scuba diving experience as a guide.
"You can't just strap on a tank and jump into the ocean," she said. "You have to know how deep you're going to go, and the deeper you go, the longer it will take to get to the surface again. And you write it all out, almost like a math equation for yourself before you get into the water."
Similarly, while working on Room, she took a piece of paper, drew a line down the centre and wrote her name on one side and "Ma" on the other. In the column under her name, she used words to describe herself. Under Ma's, she used words that defined her character.
"When you're inhabiting someone like that you have to say: That sense of helplessness is Ma's. It's not mine, and these are the reasons why I know for sure that's not me," she explained. "Ma might feel lonely; I don't. Here are all the people that are important to me and that are in my life who I could call at any moment."
She likened playing Ma to handling hazardous materials. She had to move gingerly and methodically to protect herself.
Working with the young, talented Tremblay helped buoy Larson, too. Abrahamson told an interviewer "it was tough for Brie, because she had to delve into dark places. I think she found it really helpful to have the little boy there because Jake is so much fun and he never obsesses with anything except having a great time pretending to be someone else."
Added Larson: "He became this great connector to an entire crew because you can't misbehave too badly around him, and it's hard to because he's in such a good mood and constantly laughing and joking around, keeping a set which could become quite heavy, due to the material, at a lighter place."
Still, when she was done with the 59-day shoot, Larson needed a break. She took six months off to travel, setting off for Hawaii and India, among other places. She hung out with her family, friends and her dogs. She basked in sunlight and rediscovered the glory of carbs.