The new Pokemon that was revealed recently was indeed Mewtwo and now we have a video of him transforming into his new form.
Mewtwo was first shown in Pokemon Red and Blue versions and as people speculated the similarities between this new form and Mewtwo, it turns out it was indeed him. You can check out more details on the game.
The game will be released in October this year for the 3DS. Check out the new video below.