Speaking to Vanity Fair, Phillips detailed how the two actors fell out before the cameras started rolling.
“Bob [De Niro] called me and he goes, 'Tell him he's an actor and he's got to be there, I like to hear the whole movie, and we're going to all get in a room and just read it,'” Phillips said.
“And I'm in between a rock and a hard place because Joaquin's like, 'There's no f***ing way I'm doing a read-through,' and Bob's like, 'I do read-throughs before we shoot, that's what we do.’”
Eventually Phoenix was brought in to a reading at De Niro's offices in Manhattan, but mumbled his way through it.
De Niro then invited Phoenix up to his personal office to talk things over, but Phoenix refused, saying he “felt sick” because he hadn't liked doing the read-through.
But with their director’s encouragement, the two stars met and worked out their issues, with De Niro apparently holding Phoenix by the face, kissing him and saying, “It’s going to be OK, bubbeleh.”
“It was so beautiful,” Phillips added.
However, in other anecdotes about the production it’s revealed that De Niro, who plays talk show host Murray Franklin, and Phoenix, who plays unhinged failing stand-up Arthur Fleck, barely spoke on set in an effort to stay true to their characters and acting methods.
“I didn’t like to talk to him on set,” Phoenix told Vanity Fair. “The first day we said good morning, and beyond that I don’t know that we talked much.”
De Niro confirmed this, adding, “His character and my character, we didn't need to talk about anything. We just say, 'Do the work. Relate as the characters to each other.' It makes it simpler and we don't [talk]. There's no reason to.”
That’s not to say there isn’t love.
“He is my favorite American actor,” Phoenix told the magazine.