"In the middle of the scene, hell just walk away and walk out," director Todd Phillips recently told the New York Times . "And the poor other actor thinks its them and it was never them it was always him, and he just wasnt feeling it."

Phoenix was recently confronted with a cringeworthy outtake from the shoot, in which he can be seen arguing with cinematographer Lawrence Sher before storming out, and he describes the footage as "so embarrassing." The clip surfaced during an appearance on Jimmy Kimmel Live: in the video, Phoenix scolds Sher for his "constant whispering" and tells him to "shut the f*** up."

"Sometimes movies get intense because you're a lot of people in a small space and you're trying to find something, so it can feel intense," Phoenix told Kimmel, adding: "That was supposed to be private... I'm a little embarrassed, I'm sorry about that. I'm sorry you guys had to see that."

In addition to lashing out at crew, Phoenix's specific approach to acting also clashed with the style of his co-star, Robert De Niro. Phillips recalled having to coax Phoenix into doing a table-read of the script against his wishes because that was how old pro De Niro wanted it.

"Bob called me and he goes, Tell [Phoenix] hes an actor and hes got to be there, I like to hear the whole movie, and were going to all get in a room and just read it,'" Phillips told Vanity Fair . "And Im in between a rock and a hard place because Joaquins like, 'Theres no fucking way Im doing a read-through.'"

De Niro got his own way in the end, though, so maybe Phoenix wasn't the biggest diva on set after all.