The Red Riding Hood actor has been cast as Jared in the adaptation of Twilight author Stephenie Meyer's first work outside of the franchise, reports Entertainment Weekly.
Andrew Niccol is directing the movie, with Saoirse Ronan attached for the starring role.
The Host focuses on an alien invasion in which the disembodied beings possess human hosts.
When a 'Wanderer' enters the body of human resistance fighter Melanie Stryder (Ronan), its host fights back, threatening to overwhelm it with thoughts of her lover Jared.
Max Irons is the 26-year-old son of veteran actor Jeremy Irons.
Liam Hemsworth has also been rumoured to be joining the film's cast.
Open Road Films are scheduled to begin shooting The Host in February 2012.
Watch a trailer for Red Riding Hood below: