The official Pokémon movie website has updated. Translations follow:

Extravagant Artists will Appear at a Live Stage Show Held at the Next Generation World Hobby Fair '15 Summer, Starting with Rei Yasuda, Performer of the Movie's Theme Song!

The "PokéTV Presents: A Pokémon the Movie XY Special Stage Show" will be held on the World Hobby Fair Stage at the "Next Generation World Hobby Fair '15 Summer", which takes place at Makuhari Messe Saturday June 27th and Sunday June 28th!

Rei Yasuda, performer of the theme song for "The Archdjinni of Rings: Hoopa", and Little Glee Monster, performers of the theme song for the short, will both be there!
In addition, both Tomohisa Sako, performer of "Getta Banban", the opening theme to the TV anime series "Pocket Monsters XY", and hosts of Pokemon Get TV will be there as well, making for an extravagant stage show!
You can't miss this!



There will be two shows held:
Saturday June 27th, 11:15am to 11:45am, featuring Rei Yasuda, Tomohisa Sako, Shoko Nakagawa, Yukito Nishii and Robin.
Sunday June 28th, 11:15am to 11:45am, featuring Little Glee Monster, Tomohisa Sako, Abareru-kun, Yukito Nishii and Robin.

The World Hobby Fair Stage is an open stage where the shows held can be watched by everyone. For details, see this page.

There will also be a Pokemon booth at the Next Generation WHF!
Here, we will present the very latest pre-release information on "Pokémon the movie XY: The Archdjinni of Rings - Hoopa/Pikachu and the Pokemon Musicians", which premieres Saturday July 18th!

If you bring your special pre-order movie ticket with the "Appear! Voucher" to the Pokémon booth, you'll receive a legendary Pokémon for your compatible video game right then and there! Choose one legendary Pokémon between Groudon, Kyogre, Dialga, Palkia, Giratina and Kyurem!!
The special pre-order movie ticket can also be purchased at the booth itself.

You can also try out attractions that let you experience the world of the movie.
There will also be lots of new video game information! Admission to the "Next Generation World Hobby Fair '15 Summer" is completely free!
Come visit the Pokémon Booth!!

For further information, see the Next Generation World Hobby Fair '15 Summer website

Source: http://www.pokemon-movie.jp/news/?p=1778