On the 17th of December, ONEUS' official social media accounts uploaded below image, announcing the upcoming boy group's debut concert.

ONEUS is a six member boy group formed by RBW, home to groups such as MAMAMOO, Vromance and ONEUS' brother group, upcoming boy band ONEWE. ONEWE used to be formerly known as MAS0094 as an independent band and MAS in the beginning of their contracts with RBW. With ONEWE, ONEUS released a pre-debut collaboration song called 'Last Song'.

Some of the members have already gathered some attention, as participants on different survival shows, appearances in music videos ahead of debut or being a trainee of big companies among others. Ravn (Kim Youngjo) used to be a trainee at YG, JYP and Plan A, and was supposed to debut in Victon. He also appeared on MIXNINE, ranking 27th, and made an appearance in MAMAMOO's 'Everyday' music video. Seoho appeared on Produce 101, ranking 94th, and MIXNINE, ranking 17th. Keonhee and Hwanwoong also appeared on Produce 101, ranking 33rd and 42nd. Leedo (Kim Geonhak) is a former YG trainee. And lastly, maknae Xion (Son Dongju) is the twin brother of ONEWE member and Produce 101/The Unit contestant Dongmyeong.

On the 15th, ONEUS had fans already wondering if they were going to make their debut soon with a mysterious teaser image. The concert, which will be held on the same day as the supposed release of their debut album, seems to confirm their suspicions.