President Trump's personal attorney Rudy Giuliani is now working for a "criminal family" and has lost complete control of his mental faculties, actor Robert De Niro said during a Saturday television interview.

De Niro, appearing on MSNBC's "AM Joy," made a reference to "The Godfather" to accuse Giuliani of selling out to criminal interests.

"I think he lost his mind. What a shame," he said of Giuliani, "because he had something going and then he just prostituted himself to work with Trump. How could he do that? I have no understanding of how he could [do that].

"He was a guy who used to prosecute people with the RICO [Racketeer Influenced and Corrupt Organizations] Act and so on, and now he's part of a criminal family. He's the Tom Hagan." De Niro continued. Hagan was the Corleone family's head lawyer in "The Godfather."

ROBERT DE NIRO SAYS TRUMP 'WOULDN'T LAST LONG' AS A GANGSTER

De Niro also mocked Trump, saying the president tried coming across as a gangster but wouldn't last long in the real-life criminal underworld.

"I have no idea why they follow him because he’s not even a good gangster," he said. "He can’t even keep his word about anything. I think in the real gangster world he wouldn’t last long. He lasts long in his own little real estate world... because he's the boss and he inherited all that money and he’s a fool. But, in the real world, he wouldn’t last long. That's my feeling."

The Academy Award winner pinned his hopes for the future of America on former New York City Mayor Michael Bloomberg and South Bend, Ind., Mayor Pete Buttigieg, saying both were capable of cleaning up Trump's "mess," as he put it.

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"We have a lot of making up to do, reparations to do with countries," he said. "Because, if we don’t have a president who really can show that we're growing up and we're repairing, sincerely, the damage that has been done, personally I think someone like Buttigieg would be capable of doing that. He's young, but he's got all the qualifications.

"Even Bloomberg... he's a grown-up, he's run this city for three terms... he's an executive, he hasn't done everything perfectly, but he's very, very good. He'll get us out of this mess," De Niro continued. "We are in one because we owe it to the rest of the world to do the right thing, and we're not going to do it unless we can show them that we have leadership not only in the next four years after 2020, but the four years after that, and after that."