Ask Lemmy

Oo, fuck yeah. But you gotta specify the North American 4Kids censor/cover, and not the original Japanese one.... Which was very different.

Wikipedia, on the development of the song, just because it's interesting:

John Siegler and John Loeffler wrote the lyrics to the song. Siegler produced the track, also playing keyboards, bass, and programming drum machines. David Rolfe, the vocalist for later themes of the series, played the guitar while Jason Paige provided the vocals.[3] Kati Mac, Loeffler, Ken Cummings and Louis Cortelezzi provided background vocals.[5] The song was written in G minor.[6] Siegler initially felt the show's concept was "incomprehensible" but decided it had potential after viewing its debut episode.[7] Jason Paige recorded the original theme song in four hours.[8] Paige initially received a "standard, three-figure flat fee" for the recording, but did not receive any royalties from the song. He received a one-time payment "in the mid-five figures" for the song in 2000.[8][9] Paige claimed that he "didn’t really know much about Pokémon" when he did the demo, other than a scene in the animated series that caused bouts of epileptic seizures in Japan.[8] The theme song premiered on the debut episode "Pokémon, I Choose You!" on September 8, 1998. In 1999, Paige recorded an extended version of the theme song for the album Pokémon 2.B.A. Master.[3]

According to Norman Grossfeld, the then-president of 4Kids Productions, the line "Gotta catch 'em all!" was created as a "tagline for marketing purposes that would also be included in the theme song". It is derived from the Japanese tagline "(ポケモンGETだぜ!, Pokémon getto da ze!)". One other contender for the tagline was "Catch 'em if you can", which was used in an earlier version of the theme song.[7]

From: https://en.wikipedia.org/wiki/Pok%C3%A9mon_Theme

Another interesting aside, is that 4Kids also notoriously and routinely butchered anime, famously, One Piece. So that they somehow turned out the Pokemon theme makes no sense, but that they did it by what seems like basically pure luck and taking advantage of artists, makes a lot of sense.

https://m.youtube.com/watch?v=AyhK7yxZPiU