The actor apologized a day after he launched an expletive at Trump at the Tony Awards. (You can watch that below.)
Trump called Trudeau “dishonest” and “weak” following the summit on Saturday. Trump advisers also ripped Trudeau, branding him a backstabber.
“With regards to the news today, sir, I have only two words for you: Thank you,” said Toronto Mayor John Tory to De Niro.
At the Tony Awards, De Niro launched an expletive at Trump and pumped his arms for emphasis. Many in the audience stood and cheered, while TV censors quickly bleeped out the offending words.
The anti-Trump sentiment swept backstage as playwright Tony Kushner and others from Angels in America spoke to reporters.
Kushner went even further than De Niro, calling Trump’s presidency “the Hitler mistake” that put a “borderline psychotic narcissist in the White House.”
This isn’t the first time De Niro has gone after Trump.
WATCH: De Niro’s past criticism of Donald Trump
In January of this year, the actor called Trump a “f**king idiot” in a profanity-laced rant.
— With files from The Associated Press