Kim Dong-jun, an actor and member of the K-pop group ZE:A, said he felt a lot of pressure in his role in "Korea-Khitan War," not only because it was such a large-scale project, but also when it came to portraying King Hyun-jong of the Goyreo Kingdom.

Kim said he used the pressure he felt as an opportunity to challenge himself and tried to reflect the pressure in his acting.

"Korea-Khitan War" is a 32-part historical drama produced by KBS, which narrates the story of the eighth king of Goryeo Hyun-jong and his political mentor Gen. Gang Gam-chan. The drama series follows the stories that unfold as the two characters work together to lead the kingdom to victory in a war against Khitan.

The show, which was produced in celebration of KBS' 50th anniversary and had a production cost of 27 billion won ($20.3 million), aired its last episode Sunday. The series' last episode recorded the show's highest viewership rating of 13.8 percent, according to Nielsen Korea.

In "Korea-Khitan War," Kim plays the role of Hyun-jong, a young king who grapples with the responsibilities of being the ruler of a country after his sudden ascension to the throne. Veteran actor Choi Soo-jong, who clinched three grand prizes in KBS' annual drama awards for his appearance in a slew of historical dramas such as "Legend of Ambition," "The King of Tears, Lee Bangwon," and "Dae Jo-yeong," took on the role of Gen. Gang Gam-chan, who loyally served Hyun-jong from the sidelines.

"I wondered if I deserved to take on the role of Hyun-jong," said the 32-year-old actor, during an interview with reporters on Tuesday.

"Being so nervous and pressurized at acting alongside such senior, veteran actors, I thought I bore a resemblance to Hyun-jong, and I aimed to convey such feelings in my acting," said Kim.

Kim said in "Korea-Khitan War," he focused most on depicting the growth process of Hyun-jong, who unexpectedly rises to the highest position in the country after having spent his youth in hiding and living as a monk.

"There is a drastic change in the character of Hyun-jong from the time he lived in the temples to the time he entered the palace. But the series consisted of 32 episodes, and I had to express the depth of the change (within that limit)," he said.

"During the process of becoming king, Hyun-jong took on a somewhat apprehensive and passive manner when conversing with his courtiers. However, gradually, I aimed to depict a commanding demeanor befitting a king," said Kim.

"Especially, as the series progressed, I paid more attention to my vocalization and tone," he added.

While portraying the role of Hyun-jong, Kim said he felt himself sincerely empathizing with his role.

"I felt heartache over situations that were unavoidable due to my own shortcomings and the relatively weak state of my country (in the drama). I even found myself getting angry," said Kim.

"In the early stages of the drama, it was difficult even to look at the resentful gazes people directed toward the character of Hyun-jong," he said.

Wrapping up the show, Kim said "Korea-Khitan War" was an adventure that functioned as a stepping stone for his growth as an actor.

"(I started this show) with the belief that 'there is no gain without challenging yourself.' Despite the fear I felt, there was no hesitation in my determination to participate in the (series)," said Kim.

"With every (episode) having been a challenge, both mentally and physically, I aimed to refine and improve myself," he said.