BE:FIRST / Mainstream -Music Video- | music lover reacts

GOT ME AT THE FIRST BEAT!!! We are back with another banger from the boys of BE:FIRST with their single 'Mainstream'. Thank you ‪@BAJK-s2t‬ for today's video! Subscribe for more videos! #befirst #befirstreaction #reaction #japan #japanese #japanesepop #boygroup #jpop #fyp #highlights #new #music #roadto200subs #mainstream