Y:SY

Known for

Acting

Born

January 22, 2000 (age 26)

Birthplace

Seoul, South Korea

Biography

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.

Best known work

The Game Caterers

2021

Idol School

2017

Welcome to Heal Inn

2018

We See Winter

2019

Lee Mujin Service

2022

Fromis's Room

2017

fromis_9 concert ＜LOVE FROM.＞ IN JAPAN

2023

프롤로그_프로미스의 방 엿보기

2017

Jae Joong and Friends

2023

fromis_9's Summer Night

2022

Filmography

2025
Duckbap HouseTV
as Self (1 episode)
2023
Jae Joong and FriendsTV
2023
fromis_9 concert ＜LOVE FROM.＞ IN JAPAN
2022
fromis_9's Autumn NightTV
as Self (13 episodes)
2022
fromis_9's Summer NightTV
as Self (9 episodes)
2022
Lee Mujin ServiceTV
as Guest (1 episode)
2021
The Game CaterersTV
as Self (3 episodes)
2020
The Silence Of IDOLTV
as Seoyeon (2 episodes)
2019
We See WinterTV
2018
Welcome to Heal InnTV
2017
Fromis's RoomTV
2017
프롤로그_프로미스의 방 엿보기TV
2017
Idol SchoolTV
as Self - Contestant (11 episodes)