George and Amal Clooney are donating $500,000 for a student-led gun-control march taking place next month, and Oprah Winfrey is matching the couple’s donation. “These inspiring young people remind me of the Freedom Riders of the ’60s who also said we’ve had ENOUGH and our voices will be heard,” she announced on Twitter. Later Tuesday, the Spielberg and Katzenberg families said they would also contribute $500,000 each. The event is taking place on March 24 in Washington, D.C., and the Clooneys said they will attend. The march is being organized by students from Marjory Stoneman Douglas High School, where a gunman opened fire last Wednesday, killing 17 people.