Seiji Takaiwa was the main Kamen Rider suit actor since Kamen Rider Agito and the only time he didn't play the main Kamen Rider was in Kamen Rider Kuuga and Kamen Rider Hibiki. Kuuga was played by Kenji Tominaga while Hibiki was played by Makoto Ito.
Kamen Rider Zero-One is set for a September 1st premiere on TV-Asahi, replacing Kamen Rider Zi-O at 9am.
[Source: Dengeki Hobby via SpecialForm12]