Kim Woo Seok is preparing to return to the entertainment industry following his military discharge, with an upcoming musical marking his first official project since completing his service.
The singer and actor has been cast in the original musical ‘UNDER MOONBOW,’ which is scheduled to premiere in Seoul on December 12, 2026.
On October 29, his agency, Blitzway Entertainment, announced his participation in the production.
The project will also mark Kim Woo Seok’s first musical appearance since his debut, giving him an opportunity to explore a new area of performance after establishing himself as both a singer and an actor.
‘UNDER MOONBOW’ combines an undercover investigation with a complicated relationship between two characters caught between truth and deception.
Developed as part of a broader intellectual property project connected to a drama in development at CJ ENM STUDIOS, the musical aims to bring its tense narrative to the stage through music and theatrical storytelling.
Kim Woo Seok to Play an Undercover Detective in ‘UNDER MOONBOW’
In the musical, Kim Woo Seok will portray Choi In Ha, an undercover detective who infiltrates a criminal organization to uncover the truth about its operations.
As the investigation progresses, In Ha becomes increasingly entangled with the organization’s leader, Gil Mo Hyeon, creating a conflict between professional duty and personal feelings.
The character’s journey will require Kim Woo Seok to portray the psychological challenges of maintaining a hidden identity while navigating increasingly complicated circumstances.
His performance is expected to explore the detective’s internal struggles and the emotional changes that emerge as the investigation unfolds.
Kim Woo Seok will share the role of Choi In Ha with three other performers: Yoon Ji Sung, Cha Seo Won and Lee Ju Seung.
Meanwhile, Lee Si Gang, Kang Chan, Lee Jin Hyuk and Kim Woo Jin will portray Gil Mo Hyeon, the organization’s leader.
Other cast members include Ahn Yoo Jin and Hong Ryun Hee as Senior Inspector Baek, who assigns In Ha to the undercover operation.
Jo Hyun Woo and Kim Tae Oh will play Lee Chang Hwan, Mo Hyeon’s uncle.
The production’s story centers on two individuals whose identities, loyalties and beliefs become increasingly difficult to separate.
By combining crime-related suspense with emotional conflict, ‘UNDER MOONBOW’ seeks to explore the uncertain boundary between truth and lies.
The creative team includes director Seo Yoon Mi, known for her work on musicals such as ‘Black Mary Poppins’ and ‘Aesop’s Story.’
Park Jae Hyun and Nam Ji Young will compose the music, while Ha Tae Sung will serve as music director and Hong Yu Seon will oversee choreography.
A New Chapter Following Military Service
Kim Woo Seok completed his mandatory military service on May 3, 2026, after serving in the Republic of Korea Army Band.
He enlisted in November 2024, temporarily putting his entertainment activities on hold.
Before his enlistment, he built a career spanning music and acting.
He debuted as a member of UP10TION in 2015 before gaining wider recognition through Mnet’s survival programme ‘Produce X 101’ in 2019.
He finished first in the competition and subsequently became a member of the project group X1.
Following X1’s activities, Kim Woo Seok continued his career as a solo artist while gradually expanding his acting portfolio.
His television credits include ‘Twenty-Twenty,’ ‘Bulgasal: Immortal Souls,’ ‘Night Has Come’ and ‘Social Savvy Class 101.’
His casting in ‘UNDER MOONBOW’ therefore represents both a return to the stage after military service and a new professional challenge.
Although he has experience as a singer and performer, the production will allow him to explore the demands of live musical theatre.
‘UNDER MOONBOW’ will open on December 12 at NOL Seokyung Square Scon Hall 2 in Seoul.
Preview performances and first-round ticket sales are scheduled to begin on November 6 at 11 a.m. KST through NOL and Ticketlink.
With its suspense-driven storyline and ensemble cast, the musical will introduce audiences to Kim Woo Seok’s next phase as a performer.
His debut in musical theatre is also set to be a notable milestone as he resumes his entertainment career after completing military service.
