Why is Baz Luhrmann shooting an American classic like The Great Gatsby down under? When we asked him a while back, the director was cagey, but when he cast Australian actress Isla Fisher as Myrtle, we nursed a theory that perhaps Luhrmann was trying to take advantage of the high tax rebates — often as large as 40 percent — offered by Australia to film productions that cast native actors in a high percentage of the starring roles. Luhrmann has now filled two other roles with Aussie actors: Rising star Joel Edgerton was cast today as Tom Buchanan, while unknown acting-school grad Elizabeth Debicki landed the role of Jordan Baker last week. Sorry, Gatsby aspirant Bradley Cooper … is there any way you can apply for dual citizenship? [Deadline]