Patricia Arquette has won the best supporting actress Oscar for her 12-year stint on Richard Linklater's Boyhood, The Guardian reported.
Arquette, the clear favourite after picking up awards at the Baftas and the Golden Globes, plays Olivia, the mum of Mason (Ellar Coltrane), a boy growing up in suburban Texas.
Linklater recruited Arquette to join the rest of the cast for a commitment that would last more than a decade, with the director shooting for a few days each year as the characters - and actors - grew older. Olivia, who is separated from Mason's dad (played by Ethan Hawke) before the film starts, has a rough time of it over the course of the film, falling for and breaking up with two alcoholic men before saying a tearful goodbye to Mason when he leaves for college.
In collecting the award, Arquette delivered an impassioned plea for gender equality: "To every woman who gave birth to every taxpayer and citizen of this nation: we have fought for everybody else's equal rights. It's our time to have wage equality once and for all and to fight for equal rights for women in America."
Arquette, who flirted with iconic status after starring in Tony Scott's Quentin Tarantino-scripted True Romance, appeared in very few films during the making of Boyhood, but held the lead role on the supernatural TV drama Medium between 2005-11. She told reporters at last month's Bafta ceremony that she had been paid "as much as her dog-walker" for her appearance in Linklater's low budget critical smash.
The 87th Academy Awards are taking place at the Dolby theatre in Los Angeles and are being hosted by Gone Girl star Neil Patrick Harris.