Pokémon X & Y players can now receive a serial code from GAME UK stores which grants them access to the previously-unobtainable Diancie.
This mythical Pokémon can be transferred to the upcoming Pokémon Omega Ruby & Alpha Sapphire in order to receive the Diancite, an item which allows Diancie to become Mega Diancie in-battle. The event runs from November 6 to November 28
Diancie is also available in GameStop stores in the US, where the event runs from now until November 16.