There have been other Mewtwo in the Pokémon anime, but this is the return of the original one.
After remaking the first Pokémon anime film in 2019, the original Mewtwo from the first film Pokémon: The First Movie (and the Mewtwo Returns TV anime special) returns to the anime franchise in an upcoming arc of Pokémon Journeys, with the voice actor returning for the role and a brand new visual to commemorate the occasion.
He also runs a YouTube channel about Japan stuff called TheDoctorDazza, tweets at @DoctorDazza, and posts photos of his travels on Instagram.