The film has been noted for the great chemistry that the lead pair had but the story was different off-screen. They were often at odds with each other and at one point Golsing refused to read his lines with McAdams, reported Us magazine.
Based on Nicholas Sparks' novel of the same name, the film just celebrated its 10th anniversary.
"Maybe Im 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.'
"And 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. I can't do it with her. I'm just not getting anything from this'," Cassavetes told VH1.
The director finally took it on himself to get things resolved between the pair to smooth out things during the shoot.
"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.' And 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."
The director believes that the great chemistry between the pair was helped by the tension that they had. Gosling and McAdams later dated from 2005 to 2007 with a brief reunion in 2008.
Gosling has, in earlier interviews, said that they got together only after the movie and they were not dating at the time of the shooting.