Japanese news site, Sponichi.co.jp reported that Kamen Rider 1 is confirmed to be a main character in Toei’s 40th anniversary movie of Kamen Rider OOO, Den-O, All Riders: Let’s Go Kamen Rider. The article doesn’t state if the original actor, Hiroshi Fujioka, is to appear, however it does state that the Den-Liner would be travelling to Kamen Rider 1’s world, possibly in the style of Kamen Rider Decade with a different actor. Meaning that Hiroshi could still be unconfirmed, or his out of suit actor could be replaced with another much younger, cheaper and forgettable first role actor. Don’t know about you, but I know which one I prefer. Or he could be be in-suit for the whole film…
The article also mentions that the title of the movie is a homage to the opening theme of the original Kamen Rider series; Let’s Go! Rider Kick!