George Clooney is to donate $US500,000 ($A700,000) to the “March for Our Lives” rally in Washington and will walk with students in support of gun control following last week’s shooting at a Florida high school that left 17 dead.

Clooney said he and his human rights lawyer wife, Amal, would attend next month’s protest with his wife and praised the “courage and eloquence” of the survivors of the Florida school shooting.

“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,” Clooney said in a statement.

The “March for Our Lives” event is one of several rallies being organised by students across the country in support of stronger gun laws, challenging politicians they say have failed to protect them.

Students from Marjory Stoneman Douglas High School in Florida, where a 19-year-old former student is accused of going on a rampage with a semiautomatic AR-15-style assault rifle on February 14, are assisting in planning the march.

Oprah Winfrey has pledged to match the Clooneys’ donation, writing on Twitter that she “couldn’t agree more” with the actor, who had said “our children’s lives depend on it”.

“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,” Winfrey wrote.

George and Amal, I couldn’t agree with you more. 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.

— Oprah Winfrey (@Oprah) February 20, 2018

The Ocean’s Eleven actor and his wife, who gave birth to twins Ella and Alexander in 2017, are known for donating large amounts of money to political causes.

Last year they donated $1 million to the Southern Poverty Law Center following a white supremacist rally in Charlottesville, Virginia, that led to counter-protests and the death of a woman.

-AAP