Brie Larson won the best actress Oscar on Sunday for her searing performance as a kidnapped mother in "Room," catapulting her to the top of Hollywood's A-list.
The 26-year-old Larson beat fellow nominees Cate Blanchett ("Carol"), Jennifer Lawrence ("Joy"), Charlotte Rampling ("45 Years") and Saoirse Ronan ("Brooklyn").
Larson, accepting the golden statuette, thanked early supporters of the once-obscure film including the Toronto International Film Festival.
"Thank you to the movie-goers. Thank you for going to the theatres and seeing our film," she said.
"Spotlight," a searing portrait of The Boston Globe's investigation into child sex abuse in the Catholic Church, won a surprise Oscar for best picture.
The movie, which has picked up a string of honours on its way to Oscars glory, beat rivals "The Big Short," "Bridge of Spies," "Brooklyn," "Mad Max: Fury Road," "The Martian," "Room," and "The Revenant."
Co-producer Michael Sugar, in his acceptance speech, voiced hope that the film would send a signal to the Vatican whose treatment of survivors of abuse by priests came under harsh criticism in the movie.
"This film gave a voice to survivors. And this Oscar amplifies that voice, which we hope will become a choir that will resonate all the way to the Vatican," he said.
"Pope Francis, it's time to protect the children and restore the faith," he said.
Another producer, Blye Pagon Faust, said that "Spotlight" showed the importance of a robust media amid years of financial struggles for the industry in the United States.
"We would not be here today without the heroic efforts of our reporters. Not only did they affect global change, but they absolutely show us the necessity for investigative journalism," she said.