Madonna performs on stage during the Women's March Saturday in Washington. Scores of celebrities took part.

WASHINGTON — If you wondered where many of Hollywood’s A-list celebrities had gone during President Donald Trump’s inauguration, you didn’t have to wonder any longer on Saturday, when scores of them showed up at huge women’s marches in Washington and other cities to send the new president a pointed message that he was in for a fight — and that, as so many signs said, women’s rights are human rights.

Madonna, Julia Roberts, Scarlett Johansson, Cher, Alicia Keys, Katy Perry, Emma Watson, Amy Schumer, Jake Gyllenhaal and feminist leader Gloria Steinem were just some of those at the march in Washington, where officials said the crowd could number more than half a million.

In New York, Helen Mirren, Cynthia Nixon and Whoopi Goldberg joined a crowd of protesters marching to Trump’s home at Trump Tower. In Park City, Utah, where the Sundance Film Festival was underway, TV host Chelsea Handler was joined by Charlize Theron, Kristen Stewart and more. In Los Angeles, Miley Cyrus, Jamie Lee Curtis, Demi Lovato and Jane Fonda were among thousands protesting.

In the capital, a sea of pink hats mocking the new president stretched far and wide as Madonna took to the stage.

The pop icon Cher, speaking in an interview backstage, said she hoped people could now mobilize against Trump the way they mobilized against the Vietnam War.

“I think people are more frightened than they’ve ever been,” the 70-year-old singer said.

Actress Edie Falco, of “Sopranos” and “Nurse Jackie” fame, noted: “Everyone I know is here today.”

The Washington march included plenty of men, too. Among the performers were soul artist Maxwell and Janelle Monae. “It’s because of women that we’re all here,” Maxwell said. “I’m so happy to say that I was here for the women. ”

In New York, Goldberg told a cheering crowd that “what’s at stake is everything you believe in ... We’re going to show America what we can do in New York.”