LOS ANGELES (CNN) – Friday is the day of the National School Walkout, an event conceived by a 16-year-old Connecticut student after the February shooting at Marjory Stoneman Douglas High School in Parkland, Florida. At 10:00 a.m. in each time zone, participants are going to walk out of their classes and observe a moment of silence for school shooting victims.

It is always a touchy subject when schools and protests mix, but participating students have the support of one of America’s biggest stars. Actor Robert DeNiro penned an excuse letter, like the one a parent would sign for a teacher, for anyone who may need that extra boost of encouragement to participate.

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But the tone of the letter is extremely serious. He identifies that the walkout covers plenty of legitimate reasons that someone would be absent from school: health, a memorial obligation, community service, good citizenship and education.

“I know we share the same interest for our children — a safe nurturing environment for their education and growth. I have four children and four grandchildren in school now,” the letter begins. “I would never make a frivolous request for them to miss classes.”

DeNiro goes on to call gun violence a “devastating disease,” and says that the walkout is “an opportunity to teach these kids history by encouraging them to make history.”

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“This is what good citizenship is all about,” DeNiro writes, “making things better.”

The official Twitter account of the National School Walkout shared DeNiro’s message on Wednesday, and a representative for DeNiro confirmed to CNN that he was, in fact, the author of the letter.

Friday’s walkout is also an observance of the 19th anniversary of the Columbine High School shooting.

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