HAL Laboratories introduced in late 1991 their new character, PoPoPo, in the game 『ティンクル☆ポポ』, ("Tinkle <star> PoPo").
(They probably meant to spell out "twinkle" in Katakana, but in my research on the Web, a lot of Japanese people don't seem able to differentiate "twinkle" and "tinkle" into the different Katakana トゥインクル and ティンクル pronunciations.)
Anyway, this ad presents the character that would eventually become HAL's most enduring creation, the lovable Kirby. He says here that he comes from a country called PuPuPu Land, whose citizens call themselves Tinkle PoPo. OK, whatever.
The game itself looks essentially the same as the released version (see below). The only differences seen between PoPo and the final Kirby game are the different names below his score.
And that's about it! Enjoy the pics!