Armitage, best known for playing Sir Guy of Gisborne in the BBC's recent Robin Hood series, will star opposite Martin Freeman as Bilbo Baggins in the film version of the J.R.R. Tolkien book.
"My first experience on stage was in a production of The Hobbit at the Alexandra Theatre in Birmingham," Armitage said, according to Entertainment Weekly. "I played an elf, and Gollum was a papier-mache puppet with a man offstage on a microphone.
"It's been in my childhood very prominently, so to come to it as a middle-aged man and have another look at it is a brilliant opportunity," Armitage added.
The Hobbit is scheduled to begin production in March.