The 25-year-old actor stars in the David Cronenberg-directed film as Eric Parker, a businessman who embarks upon a surreal, Odyssey-like journey across Manhattan in a stretch limo.
Based on the Don DeLillo novel of the same name, the film recently premiered at Cannes to a standing ovation.
In an interview with GQ Pattinson reveals that some of the more difficult parts of filming the movie were the sex scenes with his female co-stars.
The actor explained: "Juliette Binoche is one of my favourite actresses and within five minutes of meeting her on this we were pretending to have sex. Which wasn't in the script.
"With both sex scenes we were supposed to have finished sex before we did the scene. Both times, David was just like, 'Yeah, just have sex'. That was a little awkward."
The 26-year-old said that he was also intimidated by Soul Food actress Patricia McKenzie, who plays Kendra Hays in the movie.
"I thought that Patricia McKenzie, who I did the other sex scene with, despised me up until that day on the set. We hadn't said a single word to each other apart from when I asked, 'Where are you from?' and she literally looked me up and down.
"I was like, 'I'm not trying to do anything - I don't have any idea!' Then on the day of the sex scene she was like, 'Hey, how's it going?' I don't know what kind of preparation that was for this scene... but it definitely did something."
Cosmopolis is currently out in the UK. It is due for release in the US on August 17.
Watch a clip from Cosmopolis below: