(CNN) -- Michael Cera always plays the good guy. The 21-year-old doesn't just play good, he plays the lovable dopey and unaware kind of good. He plays the kind of guy you'd let take you to the prom when the hot guy from the basketball team dumps you.
But now the star of "Juno," "Superbad" and "Nick and Norah's Infinite Playlist," gets to play bad, or at least part of him does, in the coming-of-age comedy "Youth in Revolt," which opens in theaters today.
In the movie, Cera is the spineless, lovelorn outsider Nick Twisp, who could be a character from any other Cera movie until he creates an alter ego in the form of Francois Dillinger, the bad boy who, unlike Nick, has what it takes to woo the girl of Nick's dreams. Nick, who loves literature and Frank Sinatra, would never get the girl, even the kind of girl who likes lovable nerds. Francois can.
Francois is definitely bad and not just because he wears aviator sunglasses and tight white pants and smokes French cigarettes. He curses and sets things on fire. He does the things most teenage boys would do if they wouldn't have to face any consequences. But given the chance to create an alter ego in real life, the reticent Cera says he really doesn't know what he would try to do.
"I would probably just be cooler," Cera said. "I just can't think of a better answer. Maybe my alter ego could drive a car really fast and do dangerous things that I am afraid of doing."
Compared to the rest of young Hollywood, Cera isn't known for doing dangerous things, or for taking on dangerous roles. He has been the critics' darling since his role as George-Michael Bluth on the canceled series "Arrested Development," which he started working on when he was 14. He was ranked No. 1 on Entertainment Weekly's "30 Under 30" actor's list in 2008.
But the character of Francois, as he commits grand theft auto and arson and talks terribly dirty to the ladies, allowed Cera to push past the sweet geekdom he has been stuck in for the past half-decade.
"It was a lot of fun. I got a lot of fun things to do in this one. I got to be filthy and rude and mean," Cera said. Asked whether it was tough to turn the tables and go from being the nice guy to being a jerk, Cera laughed and said it was one of the more fun experiences he has ever had making a film.
"It wasn't hard at all," he said. "It was a blast. I had a great time the whole shoot and it was one of the most fun movie experiences I've had."
Cera's character tries hard to get the girl, maybe a little bit too hard, since for much of the movie, Francois is committing a series of felony offenses. In real life, the actor split from his longtime girlfriend, the singer and actress, Charlyne Li, over the summer. His take on relationships, for a guy in his early 20s, is remarkably simple and yet practical.
"Don't be afraid. Just be yourself and if it doesn't go well then there is someone else it will go better with," Cera said, sounding wise beyond his years.
Both Cera and the movie's production company "The Weinstein Company" have been capitalizing on the cultural zeitgeist that is the reality show "The Jersey Shore," to promote "Youth in Revolt." Cera had his hair blown out by cast-member Pauly D earlier this week in a video that quickly went viral, and filmed a special for MTV entitled "Michael Cera and the Jersey Shore."
"I just felt silly when we did it," Cera said. "It was fun but I didn't realize how long my hair was." He says he respects Pauly D for being able to style his hair in a "blow out" every day, but doesn't think he personally will be able to pull it off on a daily basis. "I think it was a one-time thing," Cera said. "I don't have the right hair for it -- so right off the bat I was at a disadvantage."
Once he's finished doing press for "Youth in Revolt," Cera has a little bit of time off before he starts making the interview rounds for his next film, "Scott Pilgrim vs. the World," in which he plays a lovelorn young adult. In the film, Scott Pilgrim is a 23-year-old in a rock band who must defeat the girl of his dreams' seven evil ex-boyfriends before he can win her heart.
As for the much-anticipated movie version of the comedy "Arrested Development," which co-starred Jason Bateman, Portia DeRossi, David Cross and Will Arnett, Cera says he still doesn't know when a full-length feature will come to fruition.
"No news yet," he said. "Just waiting on a script."