Changsub of BtoB was tagged in an Instagram Story by his gym instructor where you can see his hot body. 

Melody (BtoB fans) were so shocked to see his toned abs and muscles that made him look manly. He was discharged last month from his mandatory military service.  

He stated in his HA.DA.BANG that he exercised and maintain a healthy diet while he was still in service and he continues his habit until today.  

Check out the photo of Changsub below.