After a year of anticipation, Niantic is officially rolling out the much-requested Legendary Pokémon on Pokémon GO. Starting 22 July, Pokémon trainers will finally lay hands on Legendary birds from the first two generations.

Pokémon GO fanatics are in for a wonderful treat from Niantic this summer as Zapdos, Articuno, Lugia, Moltres, and Ho-Oh have been confirmed arriving on Saturday. The San Francisco, California-based developer unveiled Friday SGT the official trailer for Legendary Pokémon showing massive and exciting gym battles against these phenomenal creatures.

Niantic said in a statement that the revelation of Legendary Pokémon is part of the ongoing festivities of Pokémon GO's first year anniversary. "Soon, millions of Trainers around the world will be able to discover, battle, and catch these extremely rare and very powerful Pokémon," reveals Niantic.

Unique Legendary Eggs will show up at gyms intermittently. A team of trainers who will successfully take down a Legendary Raid Boss will be given a shot at catching their own Legendary Pokémon. A Legendary Pokémon does not want to leave its trainer, and as a result, the trainer will have someone else to help protect the gym in future battles as well as defeat Raid Bosses.

Niantic notes that in-game bonuses will be up for grabs at the Pokémon GO Fest in Grant Park, Chicago on Saturday. Chicago will be the jump-off point of the global event. Once trainers in the city will be able to amass enough Pokémon (the requisite number will be revealed on Saturday) during the Pokémon GO Fest Challenge Windows, the first Legendary Pokémon will start to appear at the park. Once it gets defeated, that Legendary Pokémon are set to show up in raid battles for the rest of the world.

Non-Chicago residents can watch the official live stream in Grant Park on Pokémon GO's YouTube and Twitch accounts. Trainers can also use the tag #PokemonGOFest on social media to join the global conversation.

Watch the official trailer below: