BTOB's Changsub dropped the teaser for his '1991' comeback.

According to his official social media, Changsub is releasing a pre-release single on September 2 ahead of his comeback album. His 1st full-length album '1991' coming out this fall will be filled with his "deepened experience and emotions."

Stay tuned for updates on Changsub. 

SEE ALSO: This trainee was rumored to debut every time a new rookie girl group launched over the past three years