The official X (formerly Twitter) account for the upcoming anime film adaptation of Kaori Mado’s romance novel Kimi to Hanabi to Yakusoku to (translated as You, Fireworks, and a Promise) posted the mashup music video featuring the theme song "Kienai Hanabi" ( Fireworks That Never Fade ) performed by the boy band timelesz. From May 28 to June 17, the account held a campaign to collect photos of fireworks along with memorable stories related to them. This video features the photos gathered during the campaign period, combined with footage from the film and the Nagaoka Fireworks Festival in Niigata Prefecture, which also appears in the story. The film produced by Shin-Ei Animation film is set to release in Japan on July 17, 2026 . Kimi to Hanabi to Yakusoku to x timelesz "Kienai Hanabi" Mashup Music Video Shori Sato — who voices the protagonist, Makoto Natsume — has been a member of timelesz since the time of its predecessor, Sexy Zone. As timelesz's third single (and the 29th of their entire career), "Kienai Hanabi" is scheduled for release on July 29, 2026. timelesz "Kienai Hanabi" Music Video YouTube ver. timelesz artist photo Akira Suzuki ( Tower of God Season 2 ) is directing Kimi to Hanabi to Yakusoku to at SynergySP and The Answerstudio.