Cha-Cha () is a 2024 Japanese romantic comedy-drama film directed by , starring Marika Ità  and Taishi Nakagawa. It follows the titular protagonist, a free-spirited artist and illustrator, as she meets and falls in love with an introverted man. The film is the fourth instalment in the "(not) HEROINE movies" series.
The film is the fourth instalment of the "(not) HEROINE movies" series, a project which aims to have "up-and-coming actresses" with "next-generation directors" on films which depict "heroines who are clumsy but live their lives to the fullest in the present." , who was set to direct, wrote the script with the help of Takamasa Oe, making this Sakai's first original work in seven years. She had chosen to write the film as she was "interested" in girls like Cha-Cha, who were "lonely and sad" despite being "well-liked." Oe, a good friend of hers who had collaborated with her previously, became involved once Sakai decided that she was unable to complete the screenplay on her own as she was busy with other projects. Though the film is a romantic comedy, Sakai reportedly included elements of psychological horror and thriller.
Actress and former J-pop idol Marika Ità  was cast as the lead. A producer had recommended Ità  to Sakai, after which the two met for an interview. According to Sakai, she offered Ità  the role in that first interview, finding her to be "very Cha-Cha-like." Ità  claimed to have auditioned for the role as she was intrigued by the script and found that there were many aspects of Cha-Cha which she related to. The film was publicly announced in May 2024. It was then announced in July that Taishi Nakagawa had been cast in the role of Raku, Cha-Cha's love interest, and that, Akihisa Shiono, Stefanie Arianne, Takashi Fujii, Motoki Ochiai, , , , , Nanoka Hara, Dan Kotaro, Yuki Kaji, , Rena Matsui, Dai Ikeda and would also be appearing in the film.
As the previous films in the "(not) HEROINE movies" series, ', ' and I Am What I Am, were well received, Cha-Cha was scheduled for a wider release. It premiered at the theatre in Tokyo on 24 September 2024 before opening in theatres nationwide on 11 October.
Wally Adams of EasternKicks rated the film 4 stars out of 5 and wrote that the script possesses a "deceptive resourcefulness" and that it produces "cleverly meaningful/amusing dialogue and ideas out of limited, airy or even asinine situations." He considered the soundtrack to be "among the strongest and most memorable elements befitting of the title" and that it is "hard to argue the filmmakers didnâÂÂt know what they were doing" in casting Ità Â.
Mark Schilling of The Japan Times rated the film 3 stars out of 5 and opined that while it "puts its crimes and misdemeanors in quotation marks", the "meta framing undercuts whatever tension the plot was trying to build." He further argued that the kidnapping subplot "strains credibility" and called Arianne "underused". However, he praised Ità Â, feeling that she was relatable and a "believable mix of contradictions".