Los Angeles, Mar 5 (IANS): Gary Oldman, for essaying former British Prime Minister Winston Churchill in "Darkest Hour", and Frances McDormand for her role as a grieving mother in "Three Billboards outside Ebbing, Missouri", won the best actor and best actress in a leading role categories at the 90th Academy Awards here.

McDormand, 60, pipped, among others, "The Post" star Meryl Streep, who scored her 21st nomination and the 17th in this category at the Oscars.

She has won an Academy Award over two decades after first winning the honour in 1996 for "Fargo".

In "Three Billboards...", she plays Mildred Hayes, a mother grieving over her daughter's rape and murder.

McDormand left an impact with her acceptance speech after she asked every female nominee in the room to stand up, and asked male gatekeepers to ask them about their projects and ideas not just at Oscar after-parties, but in office meetings following awards season.

As her fellow nominees stood, she said: "We all have stories to tell and projects we need financed." She urged stars to demand inclusion riders -- requirements for gender or racial diversity -- in their contracts.

Jennifer Lawrence and Jodie Foster presented the Best Actress trophy to McDormand, in a break from tradition that the previous year's Best Actor winner presents the award.

As for Oldman, it was his second nomination in the Actor in a Leading Role category. He was previously nominated for "Tinker Tailor Soldier Spy" in 2011.

While accepting the award, Oldman said: "I've lived in America for the longest time, and I am deeply grateful to her for the loves and the friendships I have made and the many wonderful gifts it has given me. My home, my livelihood, my family, and now Oscar."

He also thanked Churchill, who he said "has been marvelous company on what can be described as an incredible journey".

Oldman, 59, also took a moment to express gratitude to his 98-year-old mother.