Beyonce, Coldplay and Madonna have signed an open letter hitting out at recent US policies for jeopardising the nation's position as a "positive role model on human rights".
The music superstars are among a number of celebrities who have put their names to the message, which aims an indirect swipe at President Donald Trump and calls the battle for gender equality "the emergency and the opportunity of our time".
Published by Global Citizen in collaboration with Beyonce-founded organisation Chime For Change, the letter demands a global fight "for every girl, every woman, everywhere".
It adds: "We have reached a critical moment in history. Recent legislation and rhetoric have put decades of progress for girls and women at risk.
"All over the world, women are on the front lines, fighting for our future. Yet millions of girls and women are still denied basic equal rights. And recent policies and appointments in the United States jeopardise its position as a global leader and positive role model on human rights.
"We fight for our future, because none of us can move forward if half of us are held back."
Other notable signatories include singer John Legend, Huffington Post founder Arianna Huffington, actresses Julia Roberts, Jada Pinkett Smith and Dakota Johnson and writer Hung Huang.
Since President Trump was inaugurated in January, a series of women's protests have taken place, including a crowd of more than half a million on the streets of Washington DC the day after the ceremony.
The movement developed partly in response to a leaked tape which surfaced during Mr Trump's campaign. In the footage, which was recorded in 2005, he was overheard making crude comments about a married woman.