Child actor Yeo Jin Goo's secret to acting was meticulous monitoring. 

On Wednesday, MBC's new Weds/Thurs drama "I Miss You" revealed on-set photos of Yeo Jin Goo monitoring his own performance when the cameras stopped rolling.

Yeo Jin Goo is currently playing the younger version of Han Jung Woo, who will later be played by Park Yoo Chun.

In the still cut, Yeo Jin Goo is seriously looking at his performance, sweat dripping from his eyebrows. It shows signs of a child actor who is truly dedicated to how he is performing on camera and he seems to be taking the part quite seriously.

The production company stated, "Despite his young age, Yeo Jin Goo has a very special place in his heart for this character and he's always monitoring his performance and reflecting back on it and he's known to be an incredibly hard worker on set. He's exceeded everyone's expectations and his great acting will definitely be one of the key points in the transition to Park Yoo Chun."

Yeo Jin Goo originally caught the audience's attention with MBC's "The Moon Embracing the Sun." Viewers are wondering what kind of performance he will be able to show in this heartbreaking, tragic love story.