The Host 2013
Directed by Andrew Niccol | Starring: Emily Browning, Saoirse Ronan, Diane Kruger, William Hurt
A parasitic alien soul is injected into the body of Melanie Stryder. Instead of carrying out her race's mission of taking over the Earth, "Wanda" (as she comes to be called) forms a bond with her host and sets out to aid other free humans.