Once Upon a Time in Hollywood feels like the most personal movie Quentin Tarantino will ever make. But it also allows him to explore his fantasies, like putting himself onto the set of a TV western, a genre he greatly admires. For OUATIH, he incorporated Lancer, the actual CBS show he was using as a centerpiece for Rick Dalton, played by Leonardo DiCaprio. And Tarantino wrote the sequence quite differently, only changing his mind when DiCaprio came up with a better idea than what was in the script.

We know that the script is Tarantino’s true darling on the set, so improv is extremely rare on the set. But DiCaprio figured that the Lancer sequence needed more, and so he pitched Tarantino; Dalton had to forget his lines and completely embarrass himself, leading to a meltdown. Tarantino, expectedly, hated this, pointing to the idea that he was focusing more on being able to have his shot at directing a 1960s western the way he would direct it. “Look, I didn’t have Rick playing Caleb having a freakout in the middle of the scene because I liked my scene. There was a whole third act to that scene, and I wanted it to be my third Western right smack dab in the middle of Once Upon a Time in . . . Hollywood, so I wanted the scene to carry on playing out.”

But DiCaprio’s idea was one Tarantino couldn’t deny because it made “just perfect f*cking sense, but it wasn’t what I wanted. I was almost f*cking annoyed that it was making sense because that wasn’t what I wanted. What I really wanted was to have my Lancer [scenes] coexisting with the rest of the film. I was frustrated. I was almost f*cking annoyed that it was making sense. OK, OK, I see what you mean, goddamn it,” the director told his star. “F*ck — you’re going to fuck up my Western. You’re going to f*ck up my little Western in the middle of my goddamn movie. F*cking goddamn it. But, yeah, yeah, you’re not wrong, you’re not wrong, you son of a bitch. OK, OK, OK.”

This would all lead to a standout moment in Once Upon a Time in Hollywood: Rick Dalton having a full-on freakout in his trailer. For this, Tarantino refused to write any dialogue for DiCaprio, instead only giving him topics to rattle on about. The resulting scene is, I think, what secured DiCaprio’s Best Actor nomination.

This story — and so, so many more — is recounted in the new book, The Making of Quentin Tarantino’s Once Upon a Time in Hollywood.