Arquette, who won best supporting actress for her role in Richard Linklater's Boyhood, used her acceptance speech to advocate equal pay for women – one of the rare incursions of politics into the 87th Academy Awards.

"To every woman who gave birth to every taxpayer and citizen of this nation, we have fought for everybody else's equal rights," Arquette said.

"It's our time to have wage equality once and for all, and equal rights for women in the United States of America."

Arquette has long acted on behalf of the disadvantaged, having founded a charity to help build houses and support proper sanitation in Haiti following the destructive 2010 earthquake. She has also worked with People for the Ethical Treatment of Animals and been an advocate for breast cancer awareness.

Streep, who was also nominated in the best supporting actress category, clapped her hands together and pointed vehemently toward Arquette from the audience. Video of Streep's keen approval was immediately circulated around social media.

Arquette's speech earned wide praise from online commentators. Valerie Jarrett, a senior adviser to US President Barack Obama, tweeted: "Congrats @PattyArquette! Thx for using your speech to advocate for #EqualPay and for understanding that when women succeed, America succeeds."

Activist filmmaker Michael Moore said: "God bless you Patricia Arquette: a great actor, a brilliant citizen, you've just won the admiration of millions."

This year's Oscars have already seen debate about male and female roles in Hollywood films. Screenwriter and producer Aaron Sorkin earlier caused a stir with his argument that "year in and year out, the guy who wins the Oscar for best actor has a much higher bar to clear than the woman who wins best actress".