Donald Trump on Tuesday hit back at Robert De Niro, calling him a "very low IQ individual," after the Oscar-winning actor's expletive-laden attack on the American president on live television.
Two days after De Niro's outburst on the stage of the Tony Awards ceremony in New York, Trump said he had watched the clip "and (I) truly believe he may be punch drunk."
Representatives for De Niro did not immediately return a request for comment.
De Niro, one of the most respected American actors, twice used an expletive against Trump on Sunday, prompting loud applause from the audience of theatre actors, directors and producers at Radio City Music Hall.
The Raging Bull actor's remarks were bleeped for more than 6 million Americans watching the awards show on CBS at home.
The audience of theatre actors, directors and producers rose to their feet in applause.
Trump was on his way to Singapore to meet with North Korean leader Kim Jong Un as the Broadway awards show was taking place. He delivered his response on his Twitter account while on his way back to the United States.
"Robert De Niro, a very Low IQ individual, has received to many shots to the head by real boxers in movies. I watched him last night and truly believe he may be 'punch-drunk',” Trump tweeted.
"I guess he doesn’t realize the economy is the best it’s ever been with employment being at an all time high, and many companies pouring back into our country. Wake up Punchy!"
De Niro won an Oscar for playing American boxer Jake LaMotta in the 1980 film Raging Bull. He returned to the ring in Grudge Match in 2013 and played a boxing trainer in 2016 movie Hands of Stone.
De Niro, a noted liberal, has been increasingly critical of Trump, a Republican, at smaller show business events in the past year, but none of them had the profile enjoyed by the Tony Awards.