In May, Saoirse Ronan landed the lead role in the film adaptation of Stephenie Meyer's 2008 novel. Variety reports that various actors are now testing for the parts of Jared and Ian.
Hemsworth, Game of Thrones's Kit Harington, Spartacus: Blood and Sand's Jai Courtney and Red Riding Hood's Max Irons are reading for the role of Jared, while In Treatment's Dane DeHaan, Prom's Thomas McDonnell, The Borgias actor Augustus Prew and The Lovely Bones's Jake Abel are testing for Ian.
The Host focuses on humans fighting against extraterrestrials called Souls who invade bodies and wipe their victims' consciousness to erase their personalities.
The film is being written and directed by In Time's Andrew Niccol.
The Host is slated for release on March 29, 2013.
Watch a trailer for Andrew Niccol's latest movie In Time below: