The 13-year-old Kick-Ass star plays a killer vampire in the movie, a reworking of 2008's Let The Right One In - a film so scary Moretz's mum deemed it too shocking for her innocent eyes.
The teen tells the New York Post, "My mom won't let me watch the whole thing... I'll watch it one day, whenever my mom lets me; when I'm around 30!"
And Moretz is only allowed to watch herself on screen, if it's a teen-friendly scene. She adds, "My mum will tape it and then show me the scenes she feels are appropriate."
Moretz can't wait to see the film classics she's not currently allowed to see: "I would love to see Taxi Driver, Leon, The Professional. I think I'd be kind of dead if I snuck out to see them now. I think my mom would totally ground me forever. I get grounded just for being on my computer too long, so I think sneaking out of the house with my friends to go see an R-rated film, that would not go over well."