This is from Stephenie Meyer the writer of the Twilight saga.  It stars Saoirse Ronan and will open March 29, 2013.  Here's the description on Deadline:

Saoirse Ronan stars as Melanie Stryder, one of the last humans putting up a fight against an alien species called Souls, parasites that invade human bodies, fuse to each person’s consciousness and systematically erase their personalities.