Celebi is coming to Pokemon Go on August 20, marking the second time a Mythical Pokemon has been added to the game. It won't be arriving by itself though - it's also bringing new cosmetic items and even a few more Pokemon from the Johto region (that means Gen 2, if you're not caught up on your Poke-geography).
Being a particularly rare Pokemon, Celebi will require some extra legwork if you want to catch it. You'll start by receiving new Special Research missions from Professor Willow, which should automatically pop up in-game. These quests challenge you to play the game in a variety of ways, such as participating in Raids, walking your Buddy Pokemon, catching a specific type of Pokemon, and so forth. The Special Research quests will get tougher and tougher until you complete all of them, at which point you'll encounter the Mythical Pokemon.
All in all, it sounds very similar to how Mew (Pokemon Go's first Mythical Pokemon) was added to the game in late March earlier this year. The steps to encounter that Pokemon were broken up into eight chapters, each containing three Special Research challenges. Along with the pink-furred telepathic cat that waited at the end, each chapter also came with its own rewards, such as extra Poke Balls, eggs, or Potions. It's not known if the path to reaching Celebi will work exactly the same, but I'd say it's a relatively safe bet.
Developer Niantic didn't specify which Gen 2 Pokemon would be joining Celebi, but a recent datamine suggests that Smeargle is coming to Pokemon Go soon, so keep your eye out for this derpy-looking (but cute!) Pokemon. New avatar items and outfits will also be available starting August 20, but you'll need to level up your Johto medal first. In other words, if you haven't been catching Gen 2 Pokemon, get on that ASAP.
Get the best games and entertainment news, reviews, tips and offers delivered to your inbox every week by signing up to the GamesRadar+ newsletter today.