A big headache has cropped up for the agency masterminding the rollout of SuperM on Oct 4.

Taeyong, 24, one of the seven members of the new Korean boy band, has been accused of being a bully in his middle school years.

On Wednesday (Sept 18), the allkpop portal reported Taeyong's former classmate as saying that the singer was nice only to students whom he considered the "in" kids in school.

The classmate noted that Taeyong was among a group of students who ill-treated another student.

SM Entertainment, which is managing SuperM, said it asked Taeyong's parents to provide records of his middle-school years.

It found no evidence that disciplinary action had been taken against him.

The parents said they were not called in by the teachers to discuss any bullying.

Still, SM has deemed it prudent to get Taeyong to address the matter.

"Taeyong deeply regrets saying things that caused hurt and behaving insensitively during his middle school days, which was before he started his dreams to be a singer.

"He sends his apologies to everyone he hurt during his trainee days, and after his debut. He's currently not forgetting to reflect, and he's doing his best in every circumstance," its statement said.

SuperM's lineup draws from existing boy groups NCT, EXO and Shinee, with four members, including Taeyong, from NCT.

His controversy is an unwanted distraction for SuperM which also have to contend with juggernaut BTS whose members just ended a two-month break.