The official movie site has updated with information on the guest voice actors for this year's movies. A translation of the article follows:


It' time to announce the guest voice actors for this year's movies! The guest voice actors in the feature film "Diancie and the Cocoon of Destruction" will be Yoshiko Mita (三田佳子), Koichi Yamadera (山寺宏一), Shoko Nakagawa (中川翔子), Rika Adachi (足立梨花) and the Nakagawake comedian duo (Tsuyoshi and Reiji).

In addition, it has been decided that the narration in the co-feature short will be provided by AKB48 member Mayu Watanabe (渡辺麻友).

Now for some comments from the actors:

The actors in the feature film, "Diancie and the Cocoon of Destruction"

Yoshiko Mita (voice of Xerneas) - 三田佳子（ゼルネアス役）:

When I was first approached about voice acting, I was very surprised! (laughs) I think it might have been the sum of my long time working in these circles, living this career and my outlook on life that got me to taking this role. I am happy being able to make myself known through Pikachu and the others. In this world, I'd like to make use of the same mentality that make my grandchild(ren) like me. 初めて声優のお話を聞いた時は「あら、驚いた！」という感じでした（笑）長くこの世界でやってきて、生きてきたキャリアや人生観などトータルなもので、この役に声をかけて頂いたのかなと思いました。私の存在をピカチュウたちを通して、知ってもらえるというのは、嬉しいです。孫に好かれる精神が、この世界でも活かせればと思います。

Koichi Yamadera (voice of Ninja Riot) - 山寺宏一（ニンジャ・ライオット役）

Perfect attendance and still going! I'm really happy! But this is the first installation of "Pokémon the Movie XY", so I'll go back and remember what it's like to be a beginner, and do my best! (Although I'm always nervous anyways, since my roles are very different every time.) This time, I'm playing a thief who uses a Gekkouga. Come to think of it, when I was a child I loved this series called "Phantom Agents" (Jp. Ninja Butai Gekkou) and I'd often play ninja games... I'll try to recall those times and give it my all while acting! 皆勤賞継続中です！本当に嬉しい！でも「ポケモン・ザ・ムービーＸＹ」として初の劇場版なので、初心に帰って頑張ります！（そもそも毎回役が違うので、いつもドキドキなんですが）今回はゲッコウガを使う忍者盗賊の役。そういえば子供の頃「忍者部隊月光」という番組が大好きで、よく忍者ごっこをしていたっけ‥。その頃を思い出して精一杯演じます！！

Shoko Nakagawa (voice of Miriss Steel) - 中川翔子（ミリス・スティール役）

This is my eighth time being a guest voice actor, and for the first time in a while, I've got a human role! Since it's a role I've never played before but have been wanting to do for a while, I'm excited. This character changes expressions often, I hope you'll see a new side of me. I'll put all I've learned in these eight years into this, so I'd be happy if you came to the theaters to watch. ８年目のゲスト声優の役が、久々の人間役！今まで演じたことのない、やってみたかった役に挑戦できるので、とても楽しみです。色んな顔を見せるキャラクターなので、新たな中川翔子を見ていただけると思います。今までの８年間のすべてを込めて、がんばりたいと思いますので、是非、劇場で観て頂けると嬉しいです。

Rika Adachi (voice of Marilyn Flame) - 足立梨花（マリリン・フレイム役）

This is the happiest thing that has happened to me lately, and I got so psyched that I kept shouting, "For real? For real?" over and over (laughs). I've been playing the games since I was little and have watched the anime the whole time, so I was overjoyed about this job. I also want to do my best so children watching this movie will grow to like Pokémon even more. ここ最近で一番うれしい事だったので、テンション上がりっぱなしで、「マジですか？」「マジですか？」と連呼してしまいました（笑）小さい頃からゲームもやっていたし、アニメもずっと見ていたので、すごく嬉しいお仕事でした。この映画を観て、子供たちにさらにポケモンを好きになってもうらえるように、私もがんばりたいと思います。

The Nakagawake duo (Tsuyoshi Nakagawa: Voice of Melecie & Reiji Nakagawa: Voice of Algus Steel) - 中川家（中川剛：メレシー役、中川礼二：アルガス・スティール役）

Comment written by Reiji: "What? Why?" was our initial response when we heard about this (laugh). We're comedians, but this is our first time voice acting, so we're amateurs, but we hope not to fall behind the others and to be able to express ourselves. We don't know if the children recognize our faces, but we hope they're looking forward to [the movie] in any case. 「え、なぜだ？」それが、一番最初にこの話を聞いた時に返した言葉です。（笑）お笑いをやっていますけど、声優は初めてで、素人なので、みなさんに負けないように、自分を出せればいいのかなと思います。子供たちは、僕の顔が分かるかどうか分かりませんが、楽しみにしていただければと思います。

The actors in the short, "Pikachu, What Kind of Keys are These?"

Mayu Watanabe (Narrator) - 渡辺麻友 （ナレーション）

I'm so happy (to be in charge of the narration of the short)! I went to watch the movie "Mewtwo Strikes Back" with my family and played the games with my older sister. The Pokémon in the short are truly lovely, so it's a soothing work. I was motivated to do my best so people could enjoy it. As it premieres in the summer holidays, I hope I can help making children from all over the country come to the theaters to watch it, and make it the most wonderful work of this summer! （短編のナレーションを担当することになり）すごく嬉しいです！映画は「ミュウツーの逆襲」を家族と一緒に観に行き、ゲームも姉と一緒にやっていました。短編はポケモンたちが本当に可愛らしくて癒やされる作品。楽しんでもらえるように頑張らなくてはと感じました。夏休み公開の作品ということで、全国の子どもたちにぜひ劇場で観て頂き、この夏一番の素敵な作品になるよう、お手伝いが出来ればと思います！

Trailer

Source: http://www.pokemon-movie.jp/news/?p=1208