Kim Yoo-jung Gives Co-Star a Caricature and Thank-You Letter

Actor Jin Sun-kyu has shared a handwritten letter from his co-star Kim Yoo-jung along with a caricature she drew of him.

Jin posted photos of the gift on social media on Oct. 19. "A thank-you gift that Ga-kyung drew and wrote for me!!" he wrote. "It was a fun, happy and precious time!! I hope '100 Days of Deception' becomes a special work for everyone."

Ga-kyung is the name of Kim Yoo-jung's character in the series.

The photos show a drawing of Jin's face alongside a handwritten note. Kim Yoo-jung opened the letter with "Sun-kyu seonbae-nim," a respectful way to address a more experienced colleague in Korea. She thanked him for the comfort and encouragement he had given her on set. She also wrote that she would keep cheering him on in his future projects.

On screen, the two play opposing characters in tvN's weekend drama "100 Days of Deception", which is currently airing. Kim Yoo-jung plays Lee Ga-kyung, a spy who hides her identity to get inside the Japanese Government-General of Korea, the colonial authority that ruled the country at the time. Jin plays Sato Shinichi, the ruthless director-general of political affairs at the Government-General.

The spy romance is set in 1932 in Gyeongseong, the name Seoul went by under Japanese colonial rule. It follows a pickpocket turned spy and an interpreter working for the Government-General. The cast also includes Park Jin-young, Kim Hyun-joo and Lee Moo-saeng.

The show's ratings have been rising. It premiered on Oct. 10 with a 5.3% rating. Its fourth episode, which aired on Oct. 18, climbed to a nationwide average of 9.0%, according to Nielsen Korea.

In the Seoul metropolitan area, the episode peaked at 10.6%. It also ranked No. 1 in its time slot across all channels, including the major broadcast networks.

Although the two play enemies on screen, Kim Yoo-jung's letter highlights their close bond behind the scenes. As the series gains viewers each week, their off-screen camaraderie is adding another layer of interest to the drama.