OOO, Den-O, All Riders: Let's Go Kamen Riders (オーズ・電王・オールライダー レッツゴー仮面ライダー, Ōzu Den'ō Ōru Raidā Rettsu Gō Kamen Raidā) is a superhero film that was released on April 1, 2011, to commemorate the 40th anniversary of the Kamen Rider franchise. While the film features all of the franchise's protagonists, the main heroes of the original Kamen Rider TV series (1 and 2), Kamen Rider Den-O, and Kamen Rider OOO serve as the main characters. The film's subtitle "Let's Go Kamen Riders" is an homage to the theme song of the original series, "Let's Go!! Rider Kick" (レッツゴー！！ライダーキック, Rettsu Gō!! Raidā Kikku). The film also marks the 60th anniversary of the Toei Company, and features cameos from Kikaider, Kikaider 01, Inazuman, and Zubat from four of Shotaro Ishinomori's other works.A preview of the film was originally scheduled for March 15, 2011, but was cancelled after the venue's structure was compromised as a result of the 2011 Tōhoku earthquake and tsunami.Let's Go Kamen Riders opened at the #1 spot in the Japanese box offices in the first two weekends of its release.