Brie Larson stars in the upcoming film Room. Based on the 2010 best-selling novel by Emma Donoghue, Room tells the story of a young boy named Jack, who is being held captive in a small room along with his mother. Larson plays his mom, Ma, who was kidnapped and raped by her captor. Room, which co-stars Joan Allen and William H. Macy, depicts what happens when they are let out of captivity as well.

Room premiered at the Telluride Film Festival in September and shortly thereafter received the People’s Choice Award at the Toronto Film Festival.

“It’s a very old story but told in a contemporary way…I thought this was an amazing opportunity to show the more universal aspect of it and to get human beings to connect with it. I also thought it was a way to make a comment on some of the interesting constructs that we’ve created for our society,” Brie Larson said in an interview with CBS News.

Even though she had no clue what it felt like to be held captive for seven years, Brie Larson did what she could to prepare for playing this role.

"Lenny [Abrahamson] is the best person to go on a journey like this with," says @brielarson of #RoomMovie director. https://t.co/fh8CDi5aLm

— Room (@RoomTheMovie) October 16, 2015

“I was on this restrictive diet with the help of a nutritionist and I was working out with a trainer every day. And I was speaking with a trauma counselor,” she said. “The only aspect that I had a hard time wrapping my brain around was being in a confined space for seven years. Like seven years later, what kind of acceptance has arisen from being there for so long? When you’re given all this empty time in silence, what kind of stuff comes up?”

Brie Larson did her best to create her own silent room for one month, too.

“I just pared everything down–no cell phone and just basically stayed at home and the only time I did anything active was when I was doing these workouts.”

Even these minor changes in her life resulted in repressed moments from her past.

“I was surprised to discover that I had some memories myself that were sort of similar to Room–in the metaphorical sense — and it gave me incredible insight into another aspect of myself, which is why is I loved this project so much,” she said.

Brie Larson on #Room, life after "United States of Tara" and vacationing with Amy Poehler http://t.co/jByab01yd2 pic.twitter.com/Y8ktpjOlpx

— Huffington Post (@HuffingtonPost) October 16, 2015

Eight-year-old Jacob Tremblay plays Brie Larson’s son Jack in Room. She says he brought a sense of light and innocence to a set that was filled with a great deal of darkness.

“Making a movie is really hard and it takes participation and a lot of brain power of 100 people–and something is bound to go wrong. There’s a thousand things we need to get right in a day. It’s easier to hang on to those things and to participate in the problem. But Jacob never does. Those things are never on his radar at all. Every day on set is just super fun and a chance to play and if you have to cry in a scene, that’s super fun. So we had this energy around that would bring this lightness to everything. Nothing would ever go too dark,” Larson said.

In addition to Room, Brie Larson recently starred with Amy Schumer in Trainwreck.

Will you check out Brie Larson in Room when it starts opening in U.S. theaters on Friday?