Mew is a legendary Pokémon who first appeared in the first ever feature-length movie, Mewtwo Strikes Back. It was voiced in both English and Japanese by Koichi Yamadera.
In this movie, Mew made a couple cameo appearances at the start of the movie. A Mewtwo was cloned from Mew's DNA, extracted from Mew's eyelash. Later, Mew started appearing around New Island while Mewtwo was testing his starter Pokémon clones. Mew followed Team Rocket into the main part of the island so it could stop Mewtwo from destroying the world.
When Mewtwo's other new clones appeared, Mew came with them; however, it did not actually reappear until just a bit later. When it did appear, it tried to reason with Mewtwo, which only led to a battle between the two. Ash stopped their battle by throwing himself in the middle of it, which turned him to stone. After Ash was revived by Pokémon tears, Mewtwo flew away with all its clones and Mew went with them. At the end of the movie, Ash briefly saw Mew in the sky, though Brock and Misty didn't see anything.
Mew makes a quick appearance in the hour-length special Mewtwo Returns. Mewtwo sees it after being thrown into the Purity Spring, although, like in the first movie, it may have just been his flashback.
