The Host was a science fiction/romance novel by Stephenie Meyer.
The novel introduces an alien race, called Souls, which takes over the Earth and its inhabitants. Now the creator of TWILIGHT, Stephenie Meyer has adapted the novel into an upcoming American blockbuster.
The story line:
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.
Written and directed by Andrew Niccol, the film stars Saoirse Ronan, Max Irons, and Jake Abel. It is set to be released on March 29, 2013.
Trailer, 3rd release: