Pokémon Go: New update will introduce over 80 additional creatures

Niantic has promised to begin rolling it out to players later this week

Pokémon will also react 'in new ways' when you encounter them in the wild (Getty Images)

Pokémon Go is being treated to its first major update since it launched last summer.

It will welcome over 80 new Pokémon to the game, all of which come from the ‘Johto’ region of the Pokémon universe, which featured in Pokémon Gold and Silver.

Three of the fresh arrivals are Chikorita, Cyndaquil, and Totodile.

Players will also gain access to two new types of Berry – the Nanab Berry, which slows a Pokémon's movements, and the Pinap Berry, which doubles the amount of Candy you earn when you catch a Pokémon.

Pokémon will react “in new ways” when you encounter them in the wild too, and item carousels will give you quick access to Berries and Poke Balls directly from the encounter screen.

Niantic has also promised new evolution items you can use to evolve the new Pokémon, as well as a fresh wardrobe for trainers.

"Today is a momentous occasion for Pokémon Go as we welcome more Pokémon and build upon the encounter and capture mechanics for the passionate global community of Trainers playing the game," said Niantic boss John Hanke.

"Pokémon Go is a live experience which we'll be continuing to support and evolve in new and interesting ways for years to come."

Niantic hasn’t confirmed exactly when the update will land, but has promised to begin rolling it out “later this week”.