"George and Amal, I couldn't agree with you more," Winfrey said, referencing a statement made by the couple announcing their donation to the cause. "I am joining forces with you and will match your $500,000 donation to 'March For Our Lives.' 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." March For Our Lives was formed by survivors of the shooting at Marjory Stoneman Douglas High School that left 17 people dead. The group is planning a rally in Washington, D.C. on March 24 "to demand that a comprehensive and effective bill be immediately brought before Congress to address…gun issues," according to the organization's mission statement.Capshaw and Spielberg called the students "an inspiration to us all" and applauded their efforts "to take a stand for the benefit of this and future generations.""The young students in Florida and now across the country are already demonstrating their leadership with a confidence and maturity that belies their ages," said the couple's statement read. "We are joining in this movement with a donation of $500,000."Earlier on Tuesday, George and Amal Clooney announced they'd be making a donation in the name of their 8-month-old twins, Alexander and Ella. The couple also said they'd be attending the event. Hours later, veteran studio chief Jeffrey Katzenberg and his wife Marilyn also announced a $500,000 donation, according to Variety.