Mimey, Giovanni, and Professor Oak better prepare for their Maury Povich appearance, as Ash Ketchum will discuss his father for the first time ever in the upcoming Pokemon movie.
The identity of Ash Ketchum's father is one of the longest-running mysteries of the Pokemon anime. Ash's father is a Pokemon trainer on a journey of his own, and he was mentioned a few times in the early days of the anime, but we know almost nothing about him. Delia Ketchum has remained a regular recurring character on the show throughout its run, but even she is unwilling to bring up her deadbeat husband.
The next film in the Pokemon franchise is Pokemon the Movie: Secrets of the Jungle, which will receive an international release in 2021. The movie stars a boy named Coco, who has been raised as a son by the mythical Pokemon Zarude. Director Tetsuo Yajima was recently interviewed by Oricon News, and a segment of it has been translated by Dogasu's Backpack. According to Yajima, Ash will discuss his father for the very first time in the film.
There is a scene where Coco questions his very existence, as he is a human who was raised by a Pokemon. Ash discusses his father with Coco, though the details have yet to be revealed at this time. The movie is due to be released tomorrow in Japan, so any juicy details will likely be revealed soon.
It bears mentioning that the version of Ash in the current movies is different from the one in the anime. This version of Ash lives in a separate reality, where he went on a journey with different characters throughout the Kanto region. Some of the same characters are around, like Pikachu and Team Rocket, but it's otherwise different. It feels as if the Pokemon anime is drawing to a close and it might end without revealing who Ash's father is, so maybe the new Pokemon movie will be the only time we ever learn more about the mysterious Mr. Ketchum.
Pocket Monsters the Movie: Coco will be released in Japan on December 25, 2020. The film will be released as Pokemon the Movie: Secrets of the Jungle outside of Japan, and it will be released in 2021.
Source: Dogasu's Backpack