Na Hyun

On October 16, 2014, Na Hyun was revealed as the first member of TS Entertainment's new girl group SONAMOO. She debuted as a member of SONAMOO on December 29, 2014 with the group's first mini album Deja Vu. On September 23, 2019, it was reported that she and fellow SONAMOO member Su Min had filed to terminate their exclusive contracts with TS back in May but have yet to receive a response from them.

It was also revealed that other members may follow suit. On September 15, 2020, the law firm representing Su Min and her revealed the court had ruled in favor of the two members and that their exclusive contracts have been terminated. TS filed an appeal against the ruling, with the appellate trial not yet set.