Y:SY

Y:SY
Lee in 2024
Born
Lee Seo-yeon

(2000-01-22) January 22, 2000 (age 26)
Seoul, South Korea[citation needed]
OccupationSinger
Musical career
GenreK-pop
InstrumentVocals
Years active2017–present
Labels
Formerly ofFromis 9
Korean name
Hangul
이서연
RRI Seoyeon
MRI Sŏyŏn

Lee Seo-yeon (Korean: 이서연, born January 22, 2000), also known as Y:SY, is a South Korean singer. She is best known as a former member of the girl group Fromis 9. Lee departed from the group in February 2025 after her contract with Pledis Entertainment expired in 2024. In 2025, she signed with H1ghr Music to start her career as a solo musician.

Early life and education

Lee was born in Seoul, South Korea, and raised in Incheon, South Korea.[citation needed] She attended the School of Performing Arts Seoul before dropping out.[citation needed] At the age of 10, she joined YG Entertainment as a trainee. In 2011, she appeared in the music video for "Knock Out" by GD & TOP, marking her first public appearance in the K-pop industry.[citation needed] She was one of the trainees under YG Entertainment's pre-debut project "Future 2NE1". On July 1, 2012, YG Entertainment released dance and individual vocal performance videos of her through its official YouTube channel, introducing her as part of the trainee lineup.[citation needed] She left the company before joining Idol School.

Career

2017–2018: Idol School and debut with Fromis 9

In 2017, Lee participated in the Mnet survival show Idol School. She finished in seventh place, securing her debut as a member of the resulting girl group Fromis 9. The group officially debuted on January 24, 2018, with the release of To. Heart.

2018–2025: Time with Fromis 9

During her time in Fromis 9, Lee was recognized for her versatility in singing and dancing. She also contributed to the group's creative process, co-writing songs such as "My Night Routine," "Eye Contact," and "Starry Night".

In September 2020, she temporarily halted group activities due to a leg injury and did not participate in promotions for the EP My Little Society. On October 28, 2022, Pledis Entertainment announced that Lee would again suspend her activities for health reasons, and she returned to the group later that year.

On December 31, 2024, Fromis 9's exclusive contract with Pledis Entertainment expired. Five members of the group continued under a new label, though Lee Seo-yeon chose not to join, leaving the group in February 2025.

2025–present: Solo career

In 2025, Lee released her first solo digital single, "I Guess It's Our Last Spring". She also contributed the track "I Am You, You Are Me" to the OST of the web drama Our Secret Diary. On June 25, 2025, Lee announced a collaboration with Ejel [ko], titled "Loyal Girl". The song was released on June 30.

On July 23, it was announced that Lee had signed an exclusive contract to H1ghr Music to embark on her solo career. In November, her agency announced she would adopt a new stage name, "Y:SY", ahead of her solo debut "Naked" on November 17. On September 9, 2026, Lee released her first solo mini album, Goodies, with title track "Energy".

Philanthropy

In 2025, Lee joined World Vision Korea,'s "Give A Nice Day" campaign to support children affected by war. To promote the campaign, Lee wore the "One Day Bracelet", designed with three colors to symbolize the different situations faced by children in conflict zones.

Discography

As lead artist

Title Year Peak chart positions Album
KOR
Down.
"I Guess It's Our Last Spring"
우린 마지막 봄인가 봐		 2025 — Non-album singles
"Loyal Girl"
의리소녀, with Ejel [ko]		 —
"Naked" 135
"Energy" 2026 — Goodies
"Language" —

Music videos

Title Year Director Ref.
"Naked" 2025 Wuzlike
"Energy" 2026 Seokzoo Hong

Soundtrack appearances

Title Year Album
"I Am You, You Are Me"
넌 나고 난 너야, Zico cover		 2024 Our Secret Diary OST

Songwriting credits

Lee Seo-yeon has songwriting and composition credits on several Fromis 9 tracks:

Filmography

Television shows

References

  1. ↑ Jang, Su-min (July 27, 2017). "'아이돌학교' 이서연, YG느낌 물씬 나는 블랙핑크 '휘파람' 연습". 뉴스1 (in Korean). Retrieved April 17, 2025.
  2. ↑ 이지영 (September 29, 2017). "노지선, '아이돌학교' 최종 1등…'fromis'로 데뷔할 9인 발표". OSEN (in Korean). 네이버 연예. Retrieved April 17, 2025.
  3. ↑ 선미경 (January 11, 2018). "프로미스나인, 데뷔 타이틀곡은 '투 하트'..트랙리스트 공개". OSEN (in Korean). 네이버 연예. Retrieved April 17, 2025.
  4. ↑ Choi, Yeonju (February 28, 2024). "Lee Seo Yeon, the all-rounder idol". Weverse Magazine. Hybe. Retrieved April 17, 2025.
  5. 1 2 "Works registered under Lee Seo-yeon (이서연)". KOMCA (in Korean). Retrieved April 16, 2025.
  6. ↑ "프로미스나인, 이서연 다리 부상 어쩌나 "8인 컴백 결정" [전문]" [Fromis_9 and Lee Seoyeon's leg injury "8 people decided to come back" [Full Story]]. Archived from the original on June 29, 2021. Retrieved September 10, 2020.
  7. ↑ @realfromis_9 (October 28, 2022). "프로미스나인 향후 스케줄 관련 안내 (+ENG)" (Tweet). Retrieved October 28, 2022 – via Twitter.
  8. ↑ "[S포토] 프로미스나인 이서연, '깜찍' (2022 KBS 가요대축제)". Star Daily News (in Korean). Archived from the original on July 7, 2024. Retrieved July 7, 2024 – via Nate.
  9. ↑ Jeong, Hee-yeon (November 29, 2024). 프로미스나인 전원 하이브 탈출...플레디스 나간다 [공식] [Fromis 9 all escape from Hybe...Pledis is leaving [Official]] (in Korean). Sports Donga. Archived from the original on December 1, 2024. Retrieved November 30, 2024 – via Naver.
  10. ↑ "[인터뷰] '아이돌→연기' 이새롬 "이서연·노지선과 연락…'프나'는 내게 자랑스러운 팀"". IZE (in Korean). Retrieved April 16, 2025. In the interview, former Fromis 9 leader Lee Sae-rom mentioned only five members chose to continue: Song Ha-young, Park Ji-won, Lee Chae-young, Lee Na-gyung, and Baek Ji-heon.
  11. 1 2 An, Ha-na. "프로미스나인 이서연·에잇레코즈 뭉쳤다...'우린 마지막 봄인가 봐' 12일 발매". MBN (in Korean). Retrieved April 16, 2025 – via Nate.
  12. 1 2 Kim, Chae-yeon (January 4, 2024). "프로미스나인 이서연, 입소문 통했다..지코 '너는 나 나는 너' 정식 음원 발매". ChosunBiz (in Korean). Retrieved April 17, 2025.
  13. 1 2 Lee, Geon-woo (June 26, 2025). ""Friendship Turned into a Song"… EJel and Lee Seoyeon Bring Shades of Youth and Summer Sentiment to Life with 'Loyal Girl'". Topstarnews.
  14. ↑ Jo, Hye-jin. "'싱어게인3' 이젤, 프로미스나인 출신 이서연과 우정송 '의리소녀' 발매". Xports News (in Korean) – via Nate.
  15. ↑ Han, Soo-jin (July 23, 2025). "[단독] 프로미스나인 전 멤버 이서연, 새 둥지 찾았다...힙합명가 하이어뮤직 行". IZE.
  16. ↑ Kim, Min-ji (November 7, 2025). "'프로미스나인 출신' 이서연(Y:SY), 11월 솔로 데뷔". 뉴스1 (in Korean).
  17. ↑ 기자, 박동선 (September 1, 2026). "이서연(Y:SY), 9일 첫 미니 'GOODIES' 발매…10개월 만의 컴백 - 뉴스컬처". 뉴스컬처 (in Korean). Archived from the original on September 1, 2026. Retrieved September 9, 2026.
  18. ↑ Lee, Dae-woong (June 22, 2025). "Jung Hyuk and Lee Seoyeon Join World Vision's 'Give a Nice Day' Campaign". Christian Today.
  19. ↑ "Download Chart 2025 Weeks 47". Circle Chart. Retrieved December 2, 2025.
  20. ↑ H1GHR MUSIC (November 17, 2025). 이서연 (Y:SY) 'NAKED' Official MV. Retrieved June 15, 2026 – via YouTube.{{cite AV media}}: CS1 maint: numeric names: authors list (link)
  21. ↑ H1GHR MUSIC (September 9, 2026). 이서연 (Y:SY) 'ENERGY' Official Video. Retrieved September 9, 2026 – via YouTube.{{cite AV media}}: CS1 maint: numeric names: authors list (link)
  22. ↑ 김영록 (June 29, 2017). "'아이돌학교' 예상보다 뜨겁다…SM·YG·JYP 출신 다수 포착". 스포츠조선 (in Korean). 네이버 연예. Retrieved April 17, 2025.
  23. ↑ Park, Ah-yeong (January 7, 2024). "'복면가왕' '인센스'=214대 가왕...박정은-김태헌-이서연-최준용 정체 공개 [종합]". MBC NEWS (in Korean). Retrieved April 17, 2025.