Actor Robert De Niro took aim at President Trump on Friday, telling "The Late Show" host Stephen Colbert that Trump "has proven himself to be a total loser."

De Niro's remarks came after Colbert asked him about his previous criticism of the president and his portrayal of special counsel Robert Mueller on "Saturday Night Live."

"You know what, Bob? Give him a chance. Why won't you give the president a chance, Robert De Niro?" Colbert asked.

"No, you're right," De Niro responded. "That's what I said right after he was elected: Give him a chance. I give everybody the benefit of the doubt. This guy has proven himself to be a total loser," the actor continued, drawing cheers from the audience.

De Niro hit Trump again later in the interview, dubbing him a "wannabe gangster."

"We have a wannabe gangster in the White House now," De Niro said.

"Even gangsters have morals," he added. "This guy, he doesn't even know what that means."

De Niro has been a frequent critic of the president's throughout his administration. He took aim at the Republican Party and Trump earlier this month, warning in an interview with The Hollywood Reporter that America would not forget about "all the things that these Republicans did during the time of Trump" long after he leaves office.

The actor recently said he considered it his "civic duty" to portray Mueller on "Saturday Night Live."

"I consider it my civic duty to do that part - just to be there because [Mueller] doesn't say much, but he doesn't have to. It's that simple," De Niro said. "I might even be happier the day that Mueller puts him in handcuffs, takes him in an orange jumpsuit and puts him away for a long time," he added.