Add him to the list of people who are not fans of Trump, he said, “Donald Trump is a bad example of the country and this city".
De Niro, accompanied by actors Alec Baldwin and Mark Ruffalo, were outside Trump tower in NYC addressing outraged people.
Also present were New York Mayor Bill de Blasio, activist Al Sharpton and filmmaker Michael Moore, was meant as a "stand" against Trump on the eve of his inauguration on Friday.
Attended by thousands of people, it was held outside the Trump Hotel in New York.
Both De Niro and Baldwin were vocal in their dismay of Trump.
"These people are a disgrace, but there is hope. Trump and Pence think you're going to lay down. That's one thing about New Yorkers: You don't lay down," he said.
Sharpton also roused the crowd as he spoke after Baldwin's speech and mimicked Trump.
He said: "This is Donald Trump's hometown, but the hometown folk do not behave like Donald Trump. America is already great, and we will make it even greater."
While Moore said: "We're at a very dangerous moment in history. As bad as you think it's going to be, it's going to be worse. The good news is there are more of us than there are of them."
Ruffalo cheered the crowd and said: "Man, I needed this. Did you need this? We're coming here tonight to protect something precious to us, and that's each other."
Cynthia Nixon offered a message to the LGBTQ community, saying that "We are not going back ... we are here, we are queer and we have no fear!"
Addressing the Muslims, Mexicans and "straight while males" in the audience Nixon said: "The LGBT community has got your back."
Basically, Hollywood is not a fan of Trump, it is loud and clear!