Y:SY

Lee Seo-yeon, under the stage name Y:SY, is a South Korean singer and former member of the girl group fromis_9. Born in Seoul, South Korea (January 22, 2000), Y:SY's music career began as a trainee in YG Entertainment as one of the trainees under YG Entertainment's pre-debut project "Future 2NE1". She left the company before joining Idol School, a survival show, which led to her debut after securing seventh place. The group officially debuted on January 24, 2018, where Y:SY was recognized for her versatility in singing, dancing and rapping as well as contributing to the group's discography through co-writing songs. On December 31, 2024, fromis_9's exclusive contract with their agency expired and Y:SY chose not to continue with the group. On July 23, 2025, it was announced that Y:SY had joined a new agency to prepare for her solo music career. In November, her agency announced that her stage name is Y:SY and her official solo debut would happen on November 17, 2025, with the single "NAKED", which she co-wrote. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.