Red Velvet's Seulgi featured in BamBam's pre-single Who Are You, will be released on December 28th, drawing attention.

At 0 o'clock on December 17th, BamBam released a teaser video of Who Are You on his official SNS. In the teaser video, a mysterious woman's arm appears behind BamBam in a white suit, drawing attention. The video then sensibly captured BamBam looking at himself or thinking about something while facing a mirror.

In the second half of the teaser, BamBam in a white suit appeared again, showing a twist in which Seulgi's appearance was revealed as BamBam's face tilted to the side by a mysterious hand.