Jake Gyllenhaal reveals what gets him off — it's not what you think (VIDEO)

Nightcrawler made Jake Gyllenhaal slim down in an unhealthy way

"I mean, you hope that a movie's going to be good, but really it's about the process for me." Gyllenhaal shared when we asked him if he was surprised by the Oscar buzz for his role in this film as news stringer Lou Bloom. "I really get off on the preparation part. Even more than the performance part."

Clearly Gyllenhaal's preparation is paying off in big ways. This is a character not like any we've ever seen play him before. Aside from losing weight and creeping out his appearance, the actor also says it was mentally transformative.

"Spending as much time in the mindset of someone like Lou and really, when I start losing weight and I started staying up at night and stuff, just chemically, it's a very interesting shift in your mind. I wouldn't say it was hard or anything — or even really challenging — I would just say it was so different from how my mind works then. I was in a different mindset. You become unaware of, you know, your emotional responses to things, and they seem normal and they're not. It's like that kind of stuff. But it translates into a character, and I think that it was an incredible journey."

4 Times Jake Gyllenhaal gives us the creeps in the Nightcrawler trailer

Gyllenhaal's co-star in the film, Rene Russo, said that she was awed by Gyllenhaal's performance as well, though she didn't find him as creepy because she "knew where things were going, and I'd read the script, and I saw the preparation."

"Had I not seen all that and worked on it, then I'm sure it would be very different," Russo told us, "just for it to come at you fresh."

Photo credit: Open Road

Gyllenhaal shared that he additionally prepped for the role by shadowing two stringers around Los Angeles.

"I had done this movie End of Watch, like, a few years ago, and I was with police officers on the street pretty much four or five nights a week for five months. And, you know, went to many, many crime scenes and many accident scenes, and while I was researching that, there were stringers when I was with the police officers, there were stringers there too. So it was strange," Gyllenhaal explained

Still, the role didn't really make him sympathize with the paparazzi, despite following police officers around like photographers follow celebrities. Gyllenhaal still thinks it's different.

Jake Gyllenhaal hospitalized after taking a scene too far

"Well, I mean, I would separate the profession of people who, sort of, follow around somebody who is known or something and the thing that Lou does. He's dealing with life and death. Do you know what I mean?"

As we said in the interview, Lou is definitely an extreme. The character Gyllenhaal creates will stay in your head long after you leave the theater — along with some big questions about the society we live in.

"It just all exists on the same plane," Gyllenhaal said of media these days. "You can go to the web page of anything and you can find, like, the State of the Union alongside, like, a video of a cat falling off of a four story building and surviving."

He continued, "That's where it's sort of a comment on society. And that mentality is what feeds a character like Lou and allows him to thrive. I think that's what was fascinating to me."

Nightcrawler opens in theaters Oct. 31. You can check out the full interview with Gyllenhaal and Russo in the video above.