Trent Reznor made music that "rot inside" for 'Gone Girl'.
The Nine Inch Nails frontman wrote the soundtrack for the thriller with Atticus Ross and admits they spent a lot of time with director David Fincher to create the perfect pieces for the movie.
Trent said: "In this case, [I] read the book, read the script, spent a lot of time with David thinking about asking him what he was looking for.
"[He wanted us to] create sonically something that might appear to be perfect and pleasant on the outside but have it sort of rot inside."
Instead of writing music for a specific scene, the composers would "think about what might fit in [the film's thematic] space, almost like set design, and run it by David to see how it feels."
The process - which the pair also used to write the scores for the director's movies 'The Girl With the Dragon Tattoo' and 'The Social Network' - was time-consuming but incredibly rewarding for the songwriters.
Trent told CBS News: "It ends up being a lot more work for us as composers.
"[But] it's been just such a rewarding experience for me personally."