BAE173's Youngseo is featured in the latest debut trailer.

In the teaser, Youngseo spends a relaxing day playing video games and gets a KO. As previously reported, "BAE" stands for "Before Anyone Else," "1" stands for perfection, and "73" is a lucky number. BAE173 featuresBit, Doha, Youngseo, Muzin, J-Min, Yoojun, and Junseo as well as former X1 members Nam Dohyon and Lee Hangyul.

Check out Youngseo's debut trailer above as well as Doha's here, J-Min's here, Muzin's here, Bit's here, Yoojun's here, and Junseo's here if you missed them.