David Fincher's "Gone Girl" starring Ben Affleck, Rosamund Pike and Neil Patrick Harris will be making its debut at the New York Film Festival on Sept. 26, Variety reports.

The film is based on Gillian Flynn's bestselling thriller novel about the disappearance of Amy Dunne (Pike) on her fifth wedding anniversary. Amy's husband Nick (Affleck) quickly turns into the main suspect as clues in her disappearance reveal a double life.

However, Nick does his own investigation and finds out there is a side to Amy he's never seen before. The latest "Gone Girl" trailer revealed Desi Collings (Harris), Amy's alleged childhood stalker, who may be the key to his wife's disappearance.

Check out there trailer for the strange thriller below.

It's no secret Flynn has confirmed she had to change her story's ending in order to create a satisfying film. Fans were concerned Flynn and Fincher threw out the ending completely and the spirit of the novel would be ruined. Flynn cleared up the rumors of a complete rewrite during a Reddit AMA.

"Tell your girlfriend not to worry-those reports have been greatly exaggerated," Flynn wrote. "Of course, the script has to be different from the book in some ways-you have to find a way to externalize all those internal thoughts and you have to do more with less room and you just don't have room for everything. But the mood, tone and spirit of the book are very much intact.

"I've been very involved in the film and loved it," she continued. "Working with David Fincher is pretty much the best place to start for a screenwriter. Screenwriting definitely works different parts of your brain than writing a novel. I do love that with novels, you can really sprawl out-it feels quite decadent. With screenwriting, you have to justify every choice. It's a nice discipline, but definitely not decadent."

"Gone Girl" will debut in theaters on Oct. 3.