He may have traded furry feet and Middle Earth for a deadly infection and the undead, but don't tell Martin Freeman he's come to Australia to make a zombie movie.

"It's not a zombie film," he says in his trailer in the middle of marshy saltbush territory an hour north of Adelaide, after a hard day's filming that has left him physically and emotionally rather wrung out. "I wouldn't have come here to do a zombie film."

What is it, then?

"I think it's a film with some zombies in it, that's the absolute truth of it."