4TH UPDATE, 1:40 PM: Philanthropist and businessman Eli Broad today pledged $1 million toward the movement to end gun violence, joining a number of Hollywood heavyweights including Oprah Winfrey, Steven Spielberg and Kate Capshaw, George and Amal Clooney, Jeffrey & Marilyn Katzenberg and others.

“No one should have to endure what the students and families of Parkland suffered last week, or what too many Americans suffer daily from our country’s gun violence epidemic,” he said in a statement today. “This must stop. I’m personally donating $1 million to Everytown and joining the courageous students of Parkland and millions of Americans demanding commonsense solutions to end the gun violence crisis.”

3RD UPDATE, February 20: Oprah Winfrey has added her name to the list of Hollywood heavyweights to donate $500,000 to March For Our Lives, the gun-protest march being organized by students at Parkland, FL’s Marjorie Stoneman Douglas High School, where a former student opened fire last week and killed 17 students and teachers and wounded 16. Donations are being made through Marchforourlives.com.

Winfrey announced the donation on her social media channels just now, with a hat-tip to George and Amal Clooney who started the donation charge this morning.

Deadline will update this throughout the day if more pledges come in for a most worthy cause.

Kate Capshaw Steven Spielberg
Capshaw and Spielberg

2ND UPDATE: Steven Spielberg and Kate Capshaw have joined in the pledge started this morning by George & Amal Clooney and then by Jeffrey & Marilyn Katzenberg to help offset the costs of the March For Our Lives event in DC on March 24 to protest for meaningful gun control. Spielberg and Capshaw have matched the Clooney donation of $500,000.

George Clooney Amal Clooney
George and Amal Clooney

“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 Capshaw and Spielberg. “Kate and I applaud their efforts to take a stand for the benefit of this and future generations. They are an inspiration to us all, and we are joining in this movement with a donation of $500,000.”

UPDATED with Katzenberg pledge: George and Amal Clooney have pledged $500,000 to help underwrite the efforts of survivors of the mass shooting at Marjorie Stoneman Douglas High School in Parkland, FL, to protest for meaningful gun control.

Marilyn Katzenberg Jeffrey Katzenberg
Marilyn and Jeffrey Katzenberg

Later in the morning, Jeffrey and Marilyn Katzenberg said they would also make a $500,000 donation, and like the Clooneys join the group’s March For Our Lives event set for March 24 in Washington, D.C.

These young people — who made a powerful plea on CBS’ Face the Nation on Sunday and in other places — seem potentially to be the lightning rod that has been lacking in the attempt to hold responsible federal lawmakers taking vast sums from the NRA and refusing to enact any meaningful reforms in the areas of background checks and the production and sale of semi-automatic weapons.

“Amal and I are so inspired by the courage and eloquence of these young men and women from Stoneman Douglas High School,” Clooney said in a statement. “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, and in the name of our children Ella and Alexander, we’re donating 500,000 dollars to help pay for this groundbreaking event. Our children’s lives depend on it.”

Said Jeffrey Katzenberg: “Marilyn and I are proud to stand with the brave young leaders from Parkland, Florida, who have taken their pain and grief and turned it into action. We will join Amal and George Clooney on March 24 to stand alongside these remarkable young people. We are also donating $500,000 to March for Our Lives to support this historic event.”