NEW YORK — After weeping through the premiere screening of “My Sister’s Keeper” June 24 at AMC Lincoln Square, guests were ready for cocktails at the Central Park Boathouse after-party.

For director Nick Cassavetes, casting the tearjerker proved challenging.

Helmer not only had to find replacements for Dakota and Elle Fanning, who were originally set to play the sister duo, but he also had to persuade the powers-that-be that Cameron Diaz was right for the matriarch role, all while “begging” Jason Patric to sign on as dad.

“I thought of Cameron immediately and everyone thought that I was nuts,” Cassavetes said. “She is very funny and does very well in a certain type of movie but I decided to take her out of that and people were mad at me. I didn’t care.”

Patric explained why he said no four times before agreeing to the part.

“It’s not my type of movie but I liked what Nick wanted to say so l said let’s give it a shot,” he said.

As for releasing the drama in the middle of an action-packed summer, New Line topper Toby Emmerich pointed to Cassavetes’ “The Notebook.”

“We released that in the summer as well and it found an audience.”