The director has opened up about tensions behind the scenes on the hit 2004 film, admitting the high drama helped to make the movie the instant classic it became.
Celebrating the 10th anniversary of the film, Cassavetes told VH1: "Maybe I'm not supposed to tell this story, but they were really not getting along one day on set. Really not. And Ryan came to me, and there's 150 people standing in this big scene, and he says: "Nick, come here".
"He's doing a scene with Rachel and he says: "Would you take her out of here and bring in another actress to read off camera with me?" I said: "What?" He says" "I can't do it with her. I'm just not getting anything from this"."
Rather than fire his leading lady, Cassavetes suggested the two stars took a break and worked out their issues in private.
He added: "We went into a room with a producer; they started screaming and yelling at each other. I walked out. At that point I was smoking cigarettes. I smoked a cigarette and everybody came out like: "All right, let's do this".
"It got better after that. They had it out... I think Ryan respected her for standing up for her character and Rachel was happy to get that out in the open. The rest of the film wasn't smooth sailing, but it was smoother sailing."
Ironically, the couple became an offscreen item once filming wrapped and McAdams and Gosling dated from 2005 to 2007.
Just before they split, Gosling told GQ magazine: "(The Notebook) introduced me to one of the great loves of my life. But people do Rachel and me a disservice by assuming we were anything like the people in that movie. Rachel and my love story is a hell of a lot more romantic than that."