Armitage plays stern dwarf leader Thorin Oakenshield, whose tense relationship with Bilbo (Martin Freeman) becomes crucial as the film goes on, while Nesbitt and Turner play Bofur and Kili respectively.
"[He is] this legendary warrior, and Bilbo is essentially the antithesis of that," Armitage explained. "He is a comfortable, cosy, small man who has never experienced war.
"Initially Thorin is very dismissive of that figure, but nevertheless is profoundly changed by him."
Armitage went on to hint at the "pretty awful" future for Bilbo and Thorin's relationship in the second and third films.
Meanwhile, Nesbitt and Turner discussed the atmosphere on set, and director Peter Jackson's approach to the material.
> Martin Freeman on 'The Hobbit: An Unexpected Journey'
> Ian McKellen on returning to Middle-earth in 'The Hobbit'
The Hobbit: An Unexpected Journey is out now.
Watch the trailer below: