Confirmed. Yup the "new" Pokemon is actually Mewtwo.

[NintendoPie]

Carl2291 said:

Nah, we only get ~1 new form per Year, compared to 73542816 Mario games per Year.

I don't know. Those Genie-looking guys from Gen 5 all had new forms. That's 3 forms in one game... plus the Keldeo form... plus the two Kyurem forms... that's quite a lot.