Happy Monday, folks! How about a vaguely disturbing trailer – thepromo for Nightcrawler – to start your day? The film, starring an emaciated and cranky (that’s putting it mildly) Jake Gyllenhaal, hits theaters this Friday, so it’s star has been busy doing press rounds and making an effort to gain back that weight – all 30lbs of it.

Jake Gyllenhaal, Nightcrawler Set
Gyllenhaal was hospitalized during filming. Don't worry, it wasn't the starvation.

But the extreme transformation was all Gyllenhaal’s choice. In fact, the script, penned by Dan Gilroy (Gilroy also directed) features very little in the way of  physical description for the obsessive, ambulance-chasing cameraman Lou Bloom. But reading between the lines, Gyllenhaal decided there was only one way to do this – commit or don’t do it at all.

More: Jake Gyllenhaal Got Hospitalized On Nightcrawler Set. What's The Movie All About?

"We're talking, movie hard. I wanted to commit to it. When I believe in a character, I'll go there. I did hurt myself by mistake, not on purpose -- I hurt my hand in a scene. That was by mistake," he says. "When we talk about losing weight, it's for a finite amount of time. That's why I say it's movie hard. You're not going to be Lou Bloom for the rest of your life. The feeling I wanted was the hunger. I wanted that irritability. I wanted that feeling that you're pushing yourself."

Watch the Nightcrawler trailer below.

That’s method acting at its finest there. But as far as personality goes, the actor makes it clear that he could never identify with his character’s money-driven single-mindedness.

"It's changed for me. For me success is about my work, being able to continue to work, having choices. And then there are things that are success: my family and interactions that I think are meaningful with them," he said in an interview with USA Today. "Success is looking at myself and recognizing how I participate in something, on a day to day level. Lou only sees financial success, fame and power -- and I have to say, I understand that."