Hammer, (I can't bring myself to refer to him as "Armie") does not exactly have a ton of acting experience behind him. He's appeared in the movie Flicka and in episodes of Desperate Housewives, Veronica Mars and Arrested Development, three TV shows I've never seen.
Little experience does not mean he can't act, it just means he hasn't had much opportunity. On the plus side, he's got the build for the role: He's supposedly 6' 5" tall.
Not much else to say about this one...
Thanks to Adrian