Viewers who caught the latest episode of "High School King of Manners" witnessed a scene in which Seo In Guk was exercising so enthusiastically that he injured himself. His character falls so hard during training camp that he had to wear a sling. And that leads his secretary, played by Lee Ha Na, to think he was injured in an earthquake in Japan.

But what may have puzzled viewers is the fact that he has an ace bandage wrapped around his shoulder before he even fell.

He earned that ace bandage while filming another scene in which his character played ice hockey.

According to his agency, Jellyfish Entertainment, the actor was treated right after he injured his shoulder ligament and he returned to the set immediately after treatment. He wanted to continue shooting is scene.

"He has a shoulder guard on because he hurt his ligament, but he removes it during shoots," said a Jellyfish Entertainment representative. "He only keeps it on during breaks or when he's looking over his script."

Whether the injury he sustains working out was originally part of the script or was added after he injured himself, it is convenient as it allows him to wear a cast and rest his arm.

The naturally athletic star learned to play ice hockey especially for his "High School King of Manners" role. He took professional ice hockey lessons for two months, practicing with the Kwangwoon University hockey team and star hockey player Ahn Geun Young.

"I want to be an actor who fulfills the role assigned to me," said Seo. "If the character requires me to put on weight and look ugly, I will do the background work in order to immerse myself in that role."

Still, even with two months practice, hockey can be a rough game and simply wearing the heavy uniform can be exhausting. His character is supposed to be an ice hockey star and perhaps the best athlete on the team.

In "High School King of Manners," Seo In Guk is not just a high school student. He also pretends to be his brother, a corporate executive. Juggling school, ice hockey and corporate life requires a lot of running back and forth between his different worlds. The role could be described as a workout.

The shoulder injury is not the first time the actor was hurt on set. He cut his hand while filming the 2012 drama "Rascal Sons."

"High School King of Manners" also stars Lee Ha Na and Lee Soo Hyuk.