YECHAN of OMEGA X and HYUNGSEO of CLASS:y Release a Duet Single, “들었다놨다 (Up and Down)”

Yechan, the youngest member of K-Pop boy group OMEGA X and its sub-unit OX:N, teamed up with Hyungseo of K-Pop girl group CLASS:y and have released a new duet single, “들었다놨다 (Up and Down).” This project was produced by CIELOGROOVE, a team of producers and songwriters that is known for collaborating with Korean artists such as Kim Jaejoong, WEi, and BAE173, as well as for their work with survival programs like Peak Time on JTBC and SCOOL on SBS M/SBS FiL. 

“It feels quite nervous to release my first duet track with a female artist! For this project, I tried my best to highlight a softer voice than the energetic one which I’m more used to, and I’m glad to hear that my voice carried the emotions of the song well.” – Yechan, member of OMEGA X & OX:N

“들었다놨다(Up and Down)” features acoustic guitar rhythms and a smooth melody, expressing the excitement of falling in love and playing hard to get. The track elevated its romantic vibe with Yechan and Hyunseo’s soft yet refreshing vocal collaboration. “들었다놨다 (Up and Down)” is the second duet project from CIELOGROOVE in 2025, followed by “좋아한다 말할래 (I wanna say I love you),” featuring Songsun of TRI.BE and GK, which was released in April 2025. This new duet project also comes shortly after Yechan debuted as a member of OX:N, the first sub-unit of OMEGA X, on June 20, 2025. The four members of OX:N will hold their first fan meeting titled INTO:N in Tokyo on September 10 and 11 after connecting with fans in Korea, Shanghai, and Macao.