"He's so blatantly stupid, he's an idiot," said De Niro. "I'd like to punch him in the face. He's an embarrassment to this country."
Other celebrities took to social media to blast Donald Trump over his latest obscene comments about women.
Video from 2005 has been leaked which shows the Presidential hopeful talking about grabbing women "by the p***y".
In the video, Trump says "you can do anything" to women "when you're a star" and brags about trying to grope and kiss women.
Despite calls for him to be replaced as the Republican candidate, Trump remained defiant, tweeting his determination to see the campaign through.
But celebrities, and Hillary Clinton, were having none of it.
The recording of the "hot mic" chat between Trump and then US television presenter Billy Bush in 2005 was obtained by the Washington Post.
Both men were wearing lapel microphones as they prepared for a taped segment in which Trump, then newly married to wife Melania, would shoot a scene of Trump visiting the set of daytime soap Days Of Our Lives.
Trump, presumably unaware that the audio was being recorded, is heard telling then Access Hollywood host Bush about a recent encounter with a woman not his wife, and subsequently identified as Bush's then co-host Nancy O'Dell.
"I moved on her and I failed. I'll admit it. I did try and f*** her," Trump says in the recording published on Friday. "And I moved on her very heavily."
He then brags about how his celebrity status allows him to do "anything" to women, including grabbing "them by the p***y."
Amy Schumer slammed the billionaire in a humorous Instagram post while other stars expressed their outrage.
Soon after Tom Bergeron tweeted calling Trump an 'Orange Crosby', the hashtag #orangecosby started trending.
And it's not just celebrities outraged over Trump's remarks.
One of his followers responded by saying he couldn't "follow" him anymore due to the remark.
"Sorry to lose you but the arrogant, sexist, dehumanising sense of entitlement and power is common to both. It starts there."