Y:SY
Lee Seo-yeon, known professionally as Y:SY, is a South Korean singer-songwriter and rapper under H1GHR Music. She is a former member of the girl group fromis_9, formed through the reality survival show Idol School (2017). She left the group in 2024. She made her solo debut on November 17, 2025, with the digital single Naked.
Known for
- Lee Mujin Service (2022)
- The Game Caterers (2021)
- Jae Joong and Friends (2023)
- The Silence Of IDOL (2020)
- Idol School (2017)
- Duckbap House (2025)
- fromis_9's Summer Night (2022)
- fromis_9's Autumn Night (2022)
- Welcome to Heal Inn (2018)
- We See Winter (2019)
- fromis_9 concert ＜LOVE FROM.＞ IN JAPAN (2023)
- 프롤로그_프로미스의 방 엿보기 (2017)
- Fromis's Room (2017)