HOW DO I GET DIANCIE IN X? im dying right now trying to find it. the only give aways are in Nhật Bản if anyone has knowledge of when we as americans can get it, please speak up.

This is the best I can figure out:
The movie in Nhật Bản came out around episode 27. And that episode is coming in a few weeks to us (basically about a month). Which means when that episode comes out, the movie will probably come out soon after. However, I have a Diancie I can duplicate for bạn =)
Here's the most of the movie I can give you- the song in Japanese.