Patricia Arquette has won the Best Supporting Actress Oscar for Boyhood for her incisive portrayal of a vulnerable single mother over a 12-year period. She won over Laura Dern for Wild, Keira Knightley for The Imitation Game, Emma Stone for Birdman and Meryl Streep for Into The Woods.

It was Arquette’s first nomination, and she used her moment of Oscar glory to make an impassioned plea for equal rights for American women. “To every woman who gave birth, to every taxpayer and citizen of this nation, we have fought for everybody’s equal rights,” she said.

“It is our time to have wage equality once and for all, and equal rights for women in the United States of America,” she added to robust applause in the Dolby Theatre in Hollywood. Meryl Streep stood up and pointed to Arquette, applauding her message.

Twitter lit up with supportive messages for what many predicted would be the most memorable moment of Sunday’s gala awards ceremony. Lena Dunham tweeted simply: “PATRICIA 4 PREZ”. And filmmaker Michael Moore tweeted: “God bless you Patricia Arquette: a great actor, a brilliant citizen, you’ve just won the admiration of millions. Much love.”

Arquette, 46, was often cited by critics as one of the key factors in Richard Linklater’s groundbreaking film, shot in a dozen different segments between 2002 and 2013. Her portrayal of Olivia Evans managed to encapsulate the hopes and disappointments of her generation, portrayed with a transcendent honesty without frills.

Patricia Arquette, winner for best supporting actress for her role in Boyhood, is congratulated by lead actor in the movie Ethan Hawke (L) at the 87th Academy Awards in Hollywood, Feb 22, 2015. – Reuters/Mike Blake

Patricia Arquette accepts the award for Outstanding Female Actor in a Supporting Role for her role in Boyhood at the 21st annual Screen Actors Guild Awards in Los Angeles, Jan 25, 2015. – Reuters/Mario Anzuoni

Arquette has been the prohibitive favourite in the field since the awards season started, winning trophies at BAFTA, SAG, the Critics Choice, the Golden Globes and the Spirits.

Prior to Boyhood, Arquette had been best known for portraying a psychic in the supernatural drama series Medium for seven seasons, winning an Emmy in 2005. She also received strong critical support for starring in the last two seasons of Boardwalk Empire, and was the series lead in Medium from 2005 to 2011.

Other notable roles for the actress include Stigmata and True Romance. Arquette comes from a family of actors, including brother David Arquette, Alexis Arquette, Richmond Arquette and Rosanna Arquette. She’s the first in the family to have been nominated for an Oscar.

Arquette read her acceptance speech from a sheet of paper, concluding a lengthy thank-you list with a well-received call for wage equality and equal rights for women in the US.

Patricia Arquette backstage at Oscars: “It’s time to fight for us now”

After delivering an impassioned speech calling for wage equality that caused the likes of Meryl Streep and Jennifer Lopez to jump to their feet with applause, best supporting actress winner Patricia Arquette expanded on her comments backstage at the Academy Awards.

Asked if she was aware of Streep’s response to her speech, Arquette laughed and said no. “But I heard about it and I gave her a big hug.” She continued on to say there aren’t equal rights for women in America, because the Constitution was written for men. “Until we pass a constitutional amendment or the ERA, we won’t have anything changed.”

“Equal means equal. The older women get, the less money they make,” Arquette said. “It’s inexcusable we go around the world talking about equal rights for women in other countries. The truth is, even though we sort of feel like we have equal rights in America, just under the surface there are huge issues at play. And it’s time for all the men who love women, and gay people, and others, to fight for us now.”

When asked how she felt about former Sony head Amy Pascal’s recent remarks on wage disparity – in short, that it was up to women to ask for more, Arquette said, “I think we need federal laws that are comprehensive. People think we have equal rights. We won’t until we pass the ERA once and for all.”

Arquette also got a laugh by saying she didn’t have time to get a manicure today, which meant she wouldn’t be prepared for “the dreaded mani-cam.” She was too busy working on her passion project,, which does ecological sanitation work in the neediest communities around the world.

When people would ask about her dress she was happy to say it was made by her best friend since she was seven years old. “It’s like wearing love,” she said… – Reuters/; AFP