Lee Joon will perform his military service as a public service due to his panic disorder.

On March 30, Prain TPC published a statement announcing that the actor had been transferred to the duty of reservist on March 23.
They said: "Under the instructions of the Military Labor Administration, Lee Joon will complete his mandatory military service as a public service worker."
Lee Joon, who enlisted in October, was systematically treated for his panic disorder while carrying out his military duties. However, because his condition did not improve, he went through legal selection procedures in the army and was considered unfit for active duty.
Lee Joon is awaiting a preliminary notice from the Military Personnel Administration. We apologize that you can not show your healthy side. He will do the best he can with his remaining military service. "