Ah - yes, of course. I came across him as a previously little know actor who was given a major role in Lord of the Rings trilogy so he's been on my radar for longer, and a lot of the actors were Australian or New Zealanders so I never thought of the possibility of him being American.

Although he was, it seems, a well-known actor in New Zealand before that -there is an infamous film* in which he is naked in a bath of milk!

*The Price of Milk, released in 2000.