Chastain beat fellow nominees Marion Cotillard in "Rust and Bone," Helen Mirren in "Hitchcock," Naomi Watts in "The Impossible" and Rachel Weisz in "The Deep Blue Sea."

"I have wanted to be an actor since I was a little girl. I have worked for a really long time. I have auditioned and struggled and fought and been on the sidelines for years," a visibly moved Chastain said.

"To be here now in this moment is a beautiful feeling, to receive this encouragement and support."

She also paid tribute to film director Kathryn Bigelow, saying that she and Chastain's character Maya were "two powerful, fearless women."