After forming a “very strong bond” with North Korean leader Kim Jong-un, President Donald Trump has found a new Twitter target: Robert De Niro.

“First, I wanna say, f– Trump,” De Niro said while introducing a musical performance by Bruce Springsteen at the 2018 Tony Awards. “It’s no longer down with Trump, it’s f– Trump.”

Trump fired back two days later aboard Air Force One as he returned to the United States from Singapore, calling De Niro a “very low IQ individual” and “punch-drunk.”

Despite calling De Niro’s intelligence into question, Trump managed to use the incorrect form of “too” in his haste to respond.

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De Niro’s comments were met with a standing ovation from the crowd. Hours prior to Trump’s tweets, De Niro made a public apology from Toronto – not to the president, but rather, to the people of Canada for Trump’s behavior, according to People.

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“I just want to make a note of apology for the idiotic behavior of my president,” De Niro said. “It’s a disgrace. And I apologize to Justin Trudeau and the other people at the G-7. It’s disgusting.”

Below is a video of De Niro’s comments at the Tony Awards.