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.
Cast
fromis_9 concert ＜LOVE FROM.＞ IN JAPAN
Idol School
(Self - Contestant)
Welcome to Heal Inn
프롤로그_프로미스의 방 엿보기
Fromis's Room
The Game Caterers
(Self)
We See Winter
Lee Mujin Service
(Guest)
Jae Joong and Friends
fromis_9's Summer Night
(Self)
fromis_9's Autumn Night
(Self)
Duckbap House
(Self)
The Silence Of IDOL
(Seoyeon)