Christina Perri became famous for her track 'Jar of Hearts,' a song about a guy breaking hearts. She may have some more songwriting fodder now -- about a guy breaking into cars! The 'A Thousand Years' songstress fought off a would-be carjacker last week.

TMZ reports that Perri was attacked early Friday morning.

According to police, Perri said she was in her car and waiting to pull into a building at about 2AM PST when a strange man opened the driver's side door. The creep instructed her to "move over" and tried forcing himself into the car, but she wouldn't move. So scary!

However, the suspect picked the wrong girl to carjack, because he failed miserably at his attempt. Perri fought him off, though he did get a couple of hits in on her head and body -- but nothing serious enough to require medical attention. She also continuously honked her car horn to draw attention to the scene. Smart girl! The guy ran away, then Perri called the cops.

The police have yet to identify a suspect.

Two lessons to learn from this: Lock your car doors and don't mess with Christina Perri!