Richard is half Norwegian.
True, I haven't come across anyone who looks really similar to Jemaine but most people tend to associate him with many tall guys with dark hair and black rimmed glasses. I remember seeing pics of Taika in Green Lantern and the fact that he was playing a nerd reminded me a bit of Richard Ayoade.
They all have a dry sense of humour which adds to the comparisons. No-one comes close to our boys though.