Andra Day, Common, Miley Cyrus, Demi Lovato and Lin Manuel-Miranda give powerful performances at March for Our Lives Stars joined students for "March for Our Lives" event in D.C. on Saturday.

Musical artists and celebrities joined forces with hundreds of thousands of young people in the nation's capital for the March for Our Lives protest.

The event calling for government action to curb gun violence was organized by high school students from Marjory Stoneman Douglas High School in Parkland, Florida, where a gunman killed 17 people on Valentine's Day.

Singer Andra Day kicked off a string of powerful performances with her anthem “Rise Up.” Joining her on stage were students from Baltimore's Cardinal Shehan School. Day also teamed up with rapper Common for her song “Stand Up for Something.”

Demi Lovato, Miley Cyrus, Ariana Grande and Jennifer Hudson were some of the celebs who took part in the event.

"Hamilton" creator Lin-Manuel Miranda and "Dear Evan Hansen" star Ben Platt performed their new mashup song, "Found/Tonight." A portion of the song's proceeds is to go toward supporting March for Our Lives.

Miranda tweeted photos of himself and Platt backstage meeting student activists from Parkland.

Marching and expressing support

George Clooney and his wife, humanitarian lawyer Amal Clooney, were among the many stars who took to the streets of D.C. in solidarity of the protest. The couple also made a $500,000 donation in the name of their twin children in support of the movement.

In a statement to ABC News before the event, Clooney wrote, "Amal and I are so inspired by the courage and eloquence of these young men and women from Stoneman Douglas High School. Our family will be there on March 24 to stand side by side with this incredible generation of young people from all over the country."

Singer Miley Cyrus tweeted about marching with "heroines" in the U.S. capital.

Kim Kardashian West also joined in the action in D.C. with husband Kanye West and daughter North, tweeting, "I hope North remembers this forever."

In New York, legendary singer Paul McCartney, whose Beatles bandmate John Lennon was shot and killed in 1980, marched in New York City, wearing a shirt with the words, “We can end gun violence.”

"Sex and the City" star Cynthia Nixon, who just announced her campaign to run for governor of New York, also hit the pavement with marchers in New York City, along with Billie Jean King.

"Top Chef" star Padma Lakshmi marched with family members of Gina Montalto, one of 17 victims killed in the Parkland shooting.

In Los Angeles, "Big Little Lies" star Laura Dern marched arm-in-arm with activists wearing "We can end gun violence" T-shirts, and also took to the stage to introduce young people who made passionate pleas to end the violence.

Actress Alyssa Milano attended the L.A. rally with her family, where Molly Sims and Bette Midler were also spotted among the marchers.

Lady Gaga marched with young people and called for an end to gun violence. "School is not a place where kids should go and feel afraid for their lives," Gaga said in the video. "They should go to feel safe, to learn and to grow and to become whatever they want to be in their future."

"Scandal" star Bellamy Young marched in Dallas and Sheryl Crow came out in Nashville.

"Frozen" star Josh Gad posted videos from the marches nationwide and as far as London.

Many more stars voiced their support for March for Our Lives on social media, including Time's Up advocate Reese Witherspoon, Rose McGowan, Harry Styles, LeBron James, Zoe Saldana, Dwayne "The Rock" Johnson, Justin Timberlake and others.

Here are some star-studded social media posts in support of March for Our Lives and its student leaders:

Justin Timberlake recorded a video with Washington, D.C., Mayor Muriel Bowser, prior to the event.