The 23-year-old actress - who has been nominated for Best Actress - Motion Picture Musical or Comedy for her role in 'Lady Bird' - will be joining in the red carpet protest of women standing up against sexual harassment in Hollywood and hopes the plan will "raise awareness" and support victims.
She told 'Extra' presenter Mark Wright: "We'll all be wearing black.
"It is the most important thing, and I've never felt so encouraged and inspired and supported to use whatever voice I have and for all of these people, men and women, to be able come together and use their influence and to open up the conversation and raise awareness and support anyone who's gone through, or anyone that has questioned their safety or their stance when they're on set -- I think it's invaluable and paramount that this happens now."
Eva Longoria recently spoke about the plans for actresses to share a "moment of solidarity" on the red carpet at Sunday's (07.01.18) event, which takes place at the Beverly Hilton hotel in Beverly Hills.
She said: "This is a moment of solidarity, not a fashion moment. For years, we've sold these awards shows as women, with our gowns and colors and our beautiful faces and our glamour. This time the industry can't expect us to go up and twirl around.
"That's not what this moment is about."
'Mudbound' actress Mary J. Blige believes the campaign is important in order to stand up for women all around the world.
She said: "There's so many women that don't get a chance to speak in other industries that are not the film industry, the music industry. It's important for us to stand up for them so they can get a chance to speak.
"I am one of those women, so, you know, I don't want to go into detail about that and I haven't, but I am, and I stand with those women. I champion them."
And Allison Janney will be "proud" to wear black on the red carpet.
She confirmed: "I will be in a black dress, proud to be standing there with the other actresses."