With her Cheerios uniform tucked safely in her locker, Dianna Agron has traded in the secure confines of William McKinley High for alien territory in the 2011 sci-fi flick "I Am Number Four." The first teaser trailer released today is light on actual footage (hence the "tease"), but it gives us our first glimpse at the movie that brought adorable towheaded couple Dianna and Alex Pettyfer together.
