On June 7, it was announced that Kim Se-jeong and Kang Mi-na of Jellyfish Entertainment had returned to their agency to prepare for their official debut as members of the girl group Gugudan at the end of June.
Pada 7 Juni, diumumkan bahwa Kim Se-jeong dan Kang Mi-na dari Jellyfish Entertainment kembali ke agensi mereka untuk mempersiapkan debut resmi mereka sebagai bagian dari girl grup pertama agensi, Gugudan pada akhir Juni.