Robert De Niro and Bradley Cooper interview each other at the Tribeca Film Festival

Robert De Niro has played an abusive boxer, a wannabe assassin, a vengeful murderer and mobsters. But there’s one role you’ll never catch him taking on.

“I’ll give you one guess, then I’ll tell you,” De Niro said, with his familiar smirk. “Donald Trump.”

The answer brought a roar of laughter and applause to the more than 400 people in the audience for De Niro’s Tribeca Film Festival talk on Saturday evening with fellow actor Bradley Cooper.

The normally reticent De Niro has been incredibly critical of the current president. On April 14, De Niro even appeared as special counsel Robert Mueller on “Saturday Night Live,” which led his longtime friend and festival co-founder Jane Rosenthal to introduce him on Saturday as “a cast member on ‘SNL.’ ”

Cooper and De Niro have worked together on four films, and while they were clearly friendly, it’s historically tough to get De Niro to be chatty. After about 15 minutes of the scheduled hour, De Niro said, “OK, I’m trying to think of what else to ask him.”

It worked out for fans, however, because De Niro called filmmaker David O. Russell, who directed De Niro and Cooper in “Silver Linings Playbook,” out of the audience to join them up on stage by saying, “Help me out.”

Later on, De Niro even teased a project that he and Russell are working on together but said he didn’t want to jinx it.

“I don’t want to say what it is,” De Niro said, “but I’m hoping it’s gonna work.”

Despite the awkward silences, it was a fun discussion centered on process and the mutual respect the three men have for one another.

There was a lot of talk about Cooper’s forthcoming directorial debut, a remake of “A Star Is Born,” starring Lady Gaga.

De Niro has seen the film and said it was “terrific.”

“The movie is wonderful. And I really hope that it gets the attention that I feel it should.”

The highlight of the evening, however, belonged to Russell. Fighting through another pause and another De Niro plea to “help us,” he told about the first time they met.

De Niro was with fellow actor Joe Pesci, Russell said, and Pesci told him, taking on an exaggerated Pesci accent, “You’re gonna find out if you hang out with this guy, if you don’t give him what to say, he’s not going to say anything.”

After hanging out with him for most of an hour, everyone in the room — including De Niro — laughed along.