Watch: BTOB's Yook Sungjae Takes on Lee Changsub's 'Four Seasons, and You' in Vocal Challenge

Yook Sungjae is putting his vocals to the test. The BTOB singer took on bandmate Lee Changsub’s song ‘Four Seasons, and You’ (사계 그리고 너) in a vocal challenge clip posted to Changsub’s official YouTube channel, and the performance is already making the rounds among fans.

According to the original post on r/kpop, the clip went up on October 10 under the title ‘#육성재 님의 #사계그리고너 #이창섭 #LEECHANGSUB.’ The post credits the track as Changsub’s original, with Sungjae stepping in for the challenge.

Details are light — the clip is a straight vocal take on Changsub’s song, tagged with the vocal challenge label (261010). It surfaced on r/kpop within hours of going live on YouTube.

The pairing is a natural one: both singers are BTOB members, per the post title, making this an in-group crossover rather than a guest feature. Sungjae’s take leans on the song’s emotional build, which suits his vocal color well.

No word yet on whether Sungjae will release a fuller cover — for now, fans are getting a brief but sharp reminder of what the group’s vocal line can do.