A K-pop star will suspend all activities, his management company said, after he was accused of being a bully while at school.
Hyunjin, 20, of boy band Stray Kids, issued an apology after allegations by an unnamed former schoolmate that he was verbally abusive during his teens.
Seven other celebrities in South Korea have faced accusations in recent days but most have denied the allegations.
It comes after a similar wave of accusations about sports stars.
Last month a pair of volleyball superstars and twin sisters were removed from the Korean national team following similar allegations.
School bullying is not more of an issue in South Korea than elsewhere, our correspondents say, but in recent weeks the issue has been a topic of much debate.
On Saturday, Hyunjin's management agency JYP Entertainment said in a statement (in Korean) that the singer will "take the time to self-reflect after halting all of his activities as a celebrity".
It added: "He sincerely regrets and is self-reflecting on the fact that he hurt various people in middle school with his rough and unsuitable words."
Last week, an anonymous social media user wrote a post on an online forum detailing how Hyunjin, whose full name is Hwang Hyunjin, had been verbally abusive when they were in middle school during their early teens.
Following an investigation and interviews with the singer's former teachers and schoolmates by JYP Entertainment, his agency said that the singer has since met the accuser and apologised for his past actions in person.
Hyunjin also posted a lengthy handwritten apology on Instagram. "Whether it was intended or not, I don't think I can be forgiven at all for giving unforgettable pain to someone," he wrote.
Now that he has been suspended from work, social media reactions have been mixed over whether it was right to punish someone over something that happened years ago.
Some users said that his apology should have been enough, but others said that he deserved it, being an idol with many followers.
In the past week, other celebrities who have been accused of school bullying include Soojin of girl group (G)I_DLE, Mingyu of boy band Seventeen, Kihyun of Monsta X, and actors Kim Dong-hee, Jo Byung-gyu and Park Hye-soo.
Most have denied the allegations, but Kihyun, 27, issued an apology online last Friday for his "immature attitude and behaviour in the past".
Park Hye-soo's K-drama series Dear.M was set to premiere last Friday, but has been postponed after the 26-year-old actress was accused online of bullying middle school classmates, including physically assaulting them and demanding money from them.
Last month, volleyball star twin sisters Lee Jae-yeong and Lee Da-yeong, 24, were banned by the national team after they admitted to abusing teammates a decade ago. At least four of their former middle school teammates had alleged abuse, including punching and being threatened with a knife.
Two male volleyball stars - Song Myung-geun and Sim Kyoung-sub - were also caught in controversy after a former school teammate alleged that he had been punched by them. The athletes apologised for their behaviour and offered to sit out the rest of the season.
According to a survey by the education ministry, at least one out of every 100 elementary and secondary school students suffered some form of abuse at school in 2019.