Lee Jong Suk is thinking about when he is going to enlist. All South Korean males between the age of 18 and 35 must serve for a period of two years. At 24, he still has a few years to fulfill his mandatory military enlistment, but he doesn't want to wait too long. And at the current height of his popularity, it's not as if his fans will forget him if he's gone for two years.

This week, the actor decided to report for a physical exam at the Seoul Regional Military Manpower Administration Office. It's the first step that all Korean males take before they officially enlist. The exam determines if they have health problems that might prevent them from serving or determine the capacity in which they serve.

According to a representative from his agency, Wellmade StarM, it was the actor's decision to undergo the exam.

"He will soon report to the Military Administration Office to be tested again," said a representative from his agency. "We will soon be informed of the decision. As military service is the duty of every Korean citizen, he will fulfill it no matter how the results turn out. However, he will not be enlisting immediately, but most likely after a while. He is slowly preparing for the enlistment."

To decide when to enlist, many actors weigh a variety of factors. For example, actor Yoo Seung Ho chose to enlist early and get it over with, whereas other actors wait until they have established themselves and feel confident they will have a career to return to.

Lee Jong Suk is very popular this year and even if he enlisted tomorrow, he would definitely have a career to return to. The actor, who gained popularity through his roles in the dramas "Secret Garden," "School 2013," and "I Hear Your Voice," also appeared in the film "The Face Reader" this year. That film won a Grand Bell award for Best Picture.

And there are definitely advantages to enlisting when you are young. Younger actors are generally in better physical shape and that means it will be easier to endure the rigors of combat training. And Lee Jong Suk is currently in perhaps the best shape of his life, having trained as a competitive swimmer for his role in the film "No Breathing."

His enlistment may have to wait until he graduates from Konkuk University where he majors in professional motion pictures art. And it will certainly have to wait until he finishes working on his latest film project, the romance "Hot Blooded Youth."