8-year-old J-Pop trainee dies of myocarditis after final stage performance

Hirata Runa, an eight-year-old trainee with the DIANNA Project girl-group scheme in Nagoya, Japan, died at approximately 4am on Friday (25 Sep). Her agency confirmed the cause as myocarditis linked to influenza. This occurred just five days after she performed at the Regular Live Vol.70 concert on 20 September.

An eight-year-old J-Pop star has died from flu-linked myocarditis just five days after performing on stage - and posting a cheerful final message thanking her fans.

Cause of death and timeline

The young performer, known by her stage name Luna-chan, was born on 16 April 2018 and attended year three of primary school. She had a passion for travelling and video games. Following her final public appearance, she posted a cheerful message thanking fans. "Thank you again today," she wrote. "It was so much fun. I hope the people in part three have fun too."

An eight-year-old J-Pop star has died from flu-linked myocarditis just five days after performing on stage - and posting a cheerful final message thanking her fans.

Myocarditis involves inflammation of the heart muscle. No further medical details or treatment history have been released regarding her condition. The agency stated: "Nagoya trainee Hirata Runa has passed away due to myocarditis resulting from influenza."

Family tribute and privacy request

Runa’s wake and funeral took place with only close relatives attending. Her devastated family shared a message through her official account, noting that "A third of Runa’s life was as an idol." They asked fans to remember her: "If possible, please let her stay in a corner of your hearts as an eternal idol."

The family expressed gratitude to "friends who were kind to her, fans who supported her, the office that made her an idol, and everyone who was part of her life". The agency requested privacy, stating: "We ask that people do not make private inquiries, seek interviews or raise questions about this on social media."

Reaction from fellow trainees

Miyata Ryoka, a fellow trainee, said the news left her "at a loss for words". She announced she would pause her social media activity to mourn privately.