Way back in September of 2009, we told you about producers Steve and Paula Mae Schwartz, along with Nick Wechsler, using their own money to acquire screen rights to The Host, the first adult novel written by Stephenie Meyer, author of the Twilight series. At the same time, Andrew Niccol (Gattaca, Now) was set to write the script and direct the big-screen adaptation.

Now, Deadline reports that Saoirse Ronan (Hanna, The Lovely Bones) has just signed on to play the lead role in the film. Ronan will portray Melanie Snyder, one of the remaining few humans left on Earth after an attack by parasitic aliens called Souls. This alien species can enter a human and essentially erase their personality from within. When Melanie is invaded by a Soul named Wanderer, he finds she won’t surrender and starts to connect with her past life. Wanderer is said to be somewhat of a legend due to all the “hosts” he has invaded on several other planets.

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The Host is slated to hit theaters in 2012.