As announced, Billlie is set to make a refreshing comeback with fresh, exciting music.

On September 26 at midnight KST, Mystic Story unveiled a tantalizing music video teaser for Billlie's new track "BYOB (Bring Your Own Best Friend)." The video is a nostalgic journey into the past, bringing back the aesthetic of the early 2000s as the five members bask in the joys of camaraderie.

Billie will release their first single album, 'Side-B: Memoirs of Echo Unseen' on October 23 at 6 PM KST, and the pre-release "BYOB" on September 27 at 6 PM KST!

Meanwhile, on September 19, Mystic Story Entertainment announced that K-pop group Billlie is set to make a comeback in October with five of its members. The group's members, Siyoon, Sheon, Tsuki, Haram, and Haruna, will actively participate in the group’s activities. The quintet will be busying themselves with vibrant activities both domestically and on an international scale. Notably, Sua and Suhyeon will not be participating in this comeback.