Brie Larson plumbed her dark side portraying a traumatized young mother in the film "Room, " spending weeks isolated in her apartment, immersed in accounts of rape and child sex abuse.
It resulted in an intense, deeply felt performance — and it won Larson an Oscar for lead actress for her role as a sexually abused captive named "Ma, " raising her 5-year-old son in a 10-by-10-foot garden shed.
She high-fived her young costar, Jacob Tremblay, before she went up to accept her statuette and thanked him from the podium for "being my partner in every way through this." And then Larson showed gratitude for the one group all other winners failed to acknowledge: the audience — especially the ones who went to her difficult movie.
"Thank you to the moviegoers, " she said. "Thank you for going to the theater and seeing our films. I appreciate it."
Larson has long been the odds-on favorite to win this year, an ingénue and a relative unknown in a category dominated by motion picture academy favorites including Cate Blanchett, Jennifer Lawrence, Charlotte Rampling and Saoirse Ronan. "Room" was just Larson's second leading film role in her two-decade career.
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Her performance as Ma in the indie adaptation of Emma Donoghue's bestselling novel "Room" also earned Larson an Independent Spirit Award, a Golden Globe, a Screen Actors Guild award and the BAFTA for best actress. The film, meanwhile, earned three other Oscar nominations: for best picture, director and adapted screenplay.
Larson's big break came with the Showtime series "United States of Tara, " but she emerged as a formidable lead actor in 2013 with the small drama "Short Term 12."
Her performance as a tortured supervisor at a group home for foster kids earned her wide acclaim on the festival circuit and set her on a course for director Lenny Abrahamson's stark and moving adaptation of "Room." That performance has catapulted Larson to the lead in Warner Bros.' $190-million tent-pole "Kong: Skull Island."
While shooting a climactic escape sequence that had Ma so desperate to free her son that she vomits on him to deceive her captor into thinking the child is sick enough for a hospital, then pretending the boy has died and rolling him inside a rug so his body can be removed, the actor lost contact with reality entirely.
"You become so bizarrely present and in a moment and everything becomes so surreally real you don't have any conscious awareness of what you're doing, " she told The Times recently.
Critics raved over Larson's raw chemistry with Tremblay, her ability to draw him out and cultivate a believable rapport. Especially striking were her fluid transitions between nurturing young mother, petulant daughter and haunted survivor.
Her performance was particularly notable because Larson's career was built largely on comic supporting roles that emphasized her looks. She was the sexy rebel teen in "United States of Tara, " Jonah Hill's love interest in "21 Jump Street" and Michael Cera's bombshell ex-girlfriend in "Scott Pilgrim vs. the World." Late last summer, Larson played a suburban mom opposite Amy Schumer in "Trainwreck."
Larson, 26, is anything but an overnight success. She was a child actor, the oldest daughter of a single mom, who worked steadily on TV and flirted with a career in pop music as a teenager. Yet when she described those early years to The Times, the Sacramento native sounded almost ambivalent about fame.
"I worried that being the lead meant that the movie was about me, " she said. "And I wanted things to be about somebody else. Another cause. I don't really enjoy the attention to be on me."
For the Record
Feb. 29, 3:30 p.m.: An earlier version of this article referred to HBO's series "United States of Tara." It aired on Showtime.