Celebrities including Oprah Winfrey, Meryl Streep, and Natalie Portman have signed an open letter calling for an end to gender inequality.
The stars are among 140 signatories from the entertainment industry, which also include Reese Witherspoon, Ryan Reynolds, Amy Schumer and Thandie Newton, who have shown their support for the campaign, spearheaded by international charity ONE.
The letter is addressed to world leaders, who are told they have been put "on notice" to take action to put an end to the inequality, claiming that it leaves 130 million girls without an education and one billion women without access to a bank account.
"There is nowhere on earth where women have the same opportunities as men, but the gender gap is wider for women living in poverty," the letter reads. "Poverty is sexist. And we won't stand by while the poorest women are overlooked.
"You have the power to deliver historic changes for women this year. From the G7 to the G20; from the African Union to your annual budgets; we will push you for commitments and hold you to account for them. And, if you deliver, we will be the first to champion your progress... We won't stop until there is justice for women and girls everywhere. Because none of us are equal until all of us are equal."
The letter has also been signed by Lena Dunham, Michael Sheen, Chadwick Boseman, and Natalie Dormer as well as others outside of Hollywood, such as Facebook's Sheryl Sandberg, Chelsea Clinton, and Huffington Post founder Arianna Huffington.
One of the signatories, former "Nashville" star Connie Britton, made reference to the Time's Up movement against sexual harassment in a statement supporting the letter.
"We have seen an astounding level of attention paid to the harmful impacts that sexism and systemic gender inequality have on our society," she wrote. "We must do more to lift up and empower those who are most overlooked, so that every girl and woman has access to an education and to the same opportunities as their fellow brothers... This year, it is my hope that all of us, especially our leaders, join in the fight for full equality."