Photos of the singer were posted on an online community page of him giving autographs to a devoted fan.
Junsu is sporting a short haircut dressed in official military police uniform.
Meanwhile, the star entered the military on February 9 where he completed his basic training over the course of four weeks at Choongnam Nonsan's army training center as well as a 3-week training course to join the military police.
Junsu will be serving in the National Police Agency in Gyeonggi Province until November 2018.
Upon seeing the photos, netizens reacted in various ways, "Looking good there," "He looks like Doraemon," "Nice uniform," "Oh my his hair!"