Demi Lovato, Amy Schumer and Clooneys among celeb support at March for Our Lives

Galvanized by a shooting massacre at a Florida high school, hundreds of thousands teenagers and their supporters — including a number of celebrities — rallied in Washington, D.C., and other cities across North America to push U.S. politicians for gun control safety laws.

• March for Our Lives: Students lead massive rallies for gun control

Common and Andra Day performed their Oscar-nominated song Stand Up For Something from the 2017 film Marshall. Day kicked off the D.C. rally with her anthem Rise Up.

Hamilton creator Lin-Manuel Miranda and Dear Evan Hansen star Ben Platt performed Found/Tonight, a mashup of songs from their hit Broadway musicals. Miranda told demonstrators: "Don't give up."

Miley Cyrus, Demi Lovato and Ariana Grande, whose Manchester concert venue was the site of a terrorist bombing last year in Britain, also performed in the U.S. capital.

Jennifer Hudson, who wrapped Saturday's event with a performance of The Times They Are A Changin,' alluded to the shooting deaths of her mother, brother and seven-year-old nephew in 2008.

Human rights lawyer Amal Clooney and husband George Clooney also joined the D.C. rally, as did Kanye West, wife Kim Kardashian West and daughter, North.

In Los Angeles, Trainwreck actress Amy Schumer addressed the crowd, thanking "students and everyone here for standing up and saying 'no more.'"

"What's in it for us is knowing we're doing our part to keep our children alive," she said.

She added there is often a professional cost to taking a political stand.

"It narrows the people who will support our work. We sell half as many tickets because we're standing up for what's right," said Schumer. "And you see that politicians? You can make a little less money and be able to look at yourself in the mirror with no blood on your hands."

Singer Paul McCartney was spotted in New York City, and told CNN: "One of my best friends was killed in gun violence right around here." Fellow Beatles member John Lennon was shot to death in Manhattan in 1980.

Other famous faces lending their support to the gun control movement included Julianne Moore, Steven Spielberg, Kate Capshaw, Glenn Close, Jimmy Fallon and Cher.