DIANNA Project, a Nagoya-based talent program and girl-group scheme, said myocarditis — inflammation of the heart muscle — linked to an influenza infection killed Hirata Runa, an eight-year-old Japanese performer who used the stage name Luna-chan, who died early Friday morning, Sept. 25, 2026.
She died at around 4 a.m., according to a tribute from her family posted through her official account. She had been on stage five days earlier.
The agency said in a statement that it regretted to announce the death of one of its Nagoya trainees. Hirata was in her third year of primary school.
Agency Asks for Privacy
DIANNA Project said a wake and funeral were held with only close relatives present, following the wishes of her bereaved family. With the funeral already held in private, the agency asked the public to respect the family’s feelings and to refrain from individual inquiries or media requests about her death, or from posting questions about it on social media.
The agency also offered its deepest gratitude to the fans who had supported her and to everyone involved in her short career. Beyond the agency’s announcement, no further medical details or treatment history have been released.
Family Thanks Fellow Idols
“One third of Runa’s life was spent as an idol,” her family said in the tribute shared through her official account.
The family thanked the fellow idols close to her, the fans who followed her, the agency staff who helped make her an idol and everyone else connected to her, and said they were sorry to deliver such sudden news. They said she had loved everyone very much, asked supporters to keep a place for her in their hearts and passed on her thanks for everything up to now.
Last Concert in Nagoya
Hirata made her last appearance at DIANNA Project’s Regular Live Vol.70 concert in Nagoya, Japan, on Sept. 20. “Thank you again today. It was so much fun,” she wrote in a social media post after the show, a cheerful note of thanks to people who came to watch her. She added that she hoped the audience at the show’s third part would enjoy themselves too.
The announcement stunned supporters, who had seen her perform in apparent good health less than a week before her death.
DIANNA Project develops and markets young J-pop “idols” based on their personality and public image.
Other Losses in J-Pop
Japanese pop has mourned other performers in recent years. Singer-actor Miho Nakayama, a figure in the early J-pop scene, was found dead at her home, and her agency, Big Apple, confirmed her death on Friday, Dec. 6, 2024. She was 54.
Nakayama was born March 1, 1970, in Tokyo and launched her entertainment career in 1985, balancing music and acting from the start. She starred in director Shunji Iwai’s 1995 romance “Love Letter,” released in the United States as “When I Close My Eyes.” Nakayama is survived by a son whom she shared with her former husband, musician Hitonari Tsuji.