Joseph Gordon-Levitt enjoyed a massive summer with "The Dark Knight Rises" and bike messenger actioner "Premium Rush." In September, he's looking to bring his success to the fall movie season with "Looper," a time-travel thriller that sees Gordon-Levitt transformed like never before.

In "Looper," Gordon-Levitt plays Joe, a specialized hitman who kills targets sent back in time by mobsters from the future. As part of his contract, Joe knows that one day, he'll have to kill his future self in order to "close the loop." But when that day comes, the older Joe (Bruce Willis) has a plan to survive, putting both versions of the same man on a one-way collision course with destiny. While Gordon-Levitt playing a younger version of Willis isn't the easiest concept to buy on paper, the "Dark Knight" actor underwent heavy makeup and prosthetics to make himself look like a man who could eventually become the "Die Hard" action star. Spoiler alert: it works marvelously.

Director Rian Johnson, who previously directed Gordon-Levitt in the 2006 neo-noir "Brick," joined MTV News for Fall Movie Preview week to talk all about "Looper," time-travel, and the terrific performance delivered by Gordon-Levitt.

MTV: It feels like there are a lot of different places where "Looper" might have been born: the desire to make a time-travel thriller, the chance to see Joseph Gordon-Levitt do something very different with his performance. Where did this project start for you?

Rian Johnson: It came from the basic central idea of that sci-fi hook of a hitman in the present working for a mob in the future, and then they send his future self back as a target, and complications arise from that. I wrote that basic idea down as a short film that I never ended up filming, about ten years ago, before making "Brick." It wasn't like I was thinking it'd be great to do a sci-fi thing, or it'd be great to do a time-travel thing. It's just one of those things where you're walking around during the day and that specific idea pops in your head. You go, "Oh, that's sort of cool," and you form a story around it. That was the initial genesis. And a lot of the things you're talking about started coming into play once we were getting it together. I did want to see Joe pull that off, being the younger version of another actor. And I wanted to work with him again. It had been a while since we made "Brick" together. When I started writing the script, I wrote it with him in mind as the character.

MTV: Joseph does an amazing job playing a younger version of Bruce Willis. Whose idea was it to take the character that far, with prosthetics and everything?

Johnson: It was kind of my idea from the start that we should do something physically. I didn't think we could get away with just having Joe be Joe and Bruce be Bruce. Maybe we could have. I don't know. At the very least it felt like it would be a lot more fun to try and do something different. The extent of the makeup was really determined by how different Bruce and Joe look. Actually, I think we ended up scaling back from what we initially thought. We initially thought we would do even more of a transformation. But the fact that they look so dissimilar meant that making them actually look alike just wasn't possible. It couldn't be done. So we picked a couple of key features and made some smaller adjustments to the nose, the lips, the color of the eyes. At the end of the day, as you said, it's really Joe's performance that carries it. The makeup helps a little bit, not just the audience, but Joe as well. When he got in that makeup, you could see him transformed. You could see him have a mask to get behind. It was a physical way of him keying in on how to create the character. It was interesting to watch on set.

MTV: How did he get those mannerisms down? Did he stalk Bruce Willis for a year? Did he sleep under his bed?

Johnson: That would be such a good story. [Laughs] When we cast Bruce, he met up with Joe in L.A., and they had lunch. He came out to [the set in] New Orleans, and we went out to dinner a few times. But mostly, Joe studied Bruce's movies, especially his recent movies. He wasn't really trying to imitate how Bruce was when he was younger. He was trying to create a younger version of the guy Bruce is now, if that makes sense. So he put the audio from "Sin City," for example, on his iPod and listened to it over and over again. Bruce recorded that opening voice-over that Joe gives at the beginning of ["Looper"], and he sent that recording to Joe so he could listen to how he specifically delivers those lines. That was very helpful. It was a lot of that kind of homework.

MTV: There's a great, big scene with the two Joes, where the topic of time travel gets brought up. Bruce sort of brushes it off with this "don't think too hard, it'll make your head hurt" attitude. But you had rules for how time travel works in "Looper," right?

Johnson: Absolutely. I came up with my own internal logic for how time travel works. But part of that logic was the notion that this is kind of like a foreign body to our universe, that time travel isn't something that's supposed to happen. It's sort of messy, the way the universe adjusts to it. It's like a foreign body being introduced to this system. The system doesn't know how to deal with it. So a bit of messiness was essential. That said, I did have my own logic for how the world handled time travel. Dispelling it in that scene isn't so much about covering up a lack of logic behind it. [Laughs] It's more about, narratively, I realized more and more as we got deeper into making the movie, it wasn't what matters, not even to the audience at that point. It's fun to dig into and talk about, but if the movie is successful, it's hopefully a thing where time travel sets up the situation, and the characters have to deal with the situation. That's the drama of it, as opposed to the fun of it being tracking down all these different levels of time travel. It was about keeping things narratively as tame as possible so that you have the brain power to put your attention on what the movie is focusing on, which is, how are these characters going to resolve the situation they're in?

MTV: A few years have passed since you and Joe worked together on "Brick," and his career has gone in a really great direction since then. How many people can say they starred in a Christopher Nolan "Batman" film? In your experience with where you guys were while working on "Brick" to where you guys are now, what observations do you have about the kind of actor Joseph has become?

Johnson: It's hard for me to say, because it was a while ago for me as well. Over the course of making "The Brothers Bloom" and now "Looper," I feel like I've changed quite a bit and learned so much also. But what strikes me more than how he's changed is how he's stayed the same. The guy that I met, ten years or so ago, he was just starting to reengage with features, but had a really clear idea in his head about what drove him and what excited him about making movies. That was his only motivation for picking any project: is he excited about the story and the director? There was no other reason for him to pick "Brick." I was this unknown kid who had a weird script and, for whatever reason, he got excited about it. That's why he did things then, and nowadays, making Chris Nolan "Batman" movies, it's the same thing now. He gets genuinely excited about the story and the people who are telling it. Seeing that continuity go all the way through, it's a very clear path. Just as a friend of his, it's been fun to see him take this huge rise in the past couple of years. It's not surprising, but it's fun to see a friend do well.

From "Perks" to "Breaking Dawn," "The Hobbit" to "Skyfall," the MTV Movies team is delving into the hottest upcoming flicks in our 2012 Fall Movie Preview. Check back daily for exclusive clips, photos and interviews with the films' biggest stars.