Sung Si Kyung returns with new self-produced OST for JTBC's 'Surely Tomorrow'

Sung Si Kyung reaffirms his reputation as the “King of Drama OSTs” with a new track that once again showcases his vocal and musical prowess.

The singer will meet listeners on December 4 with the pre-released single “On Some Days, With Some Feelings.”

The song serves as an OST for JTBC’s new weekend drama 'Surely Tomorrow' (written by Yoo Young Ah, directed by Lim Hyun Wook, produced by SLL, IN, and Geulmoi). Sung Si Kyung not only performs the track but also took charge of the composition and full production, elevating its quality from every angle.

Inspired by the drama’s protagonist Kyung Do (played by Park Seo Joon), the track is filled with Sung Si Kyung’s signature emotional depth and refined musical sensibility.

Its calm yet resonant melody was crafted by Sung Si Kyung himself, while esteemed lyricist Shim Hyun Bo — known for countless hits — penned the lyrics. Top-tier arrangers Gooreum and Jeon Jin Hee also joined the project, adding further richness and polish to the song.

“On Some Days, With Some Feelings” is set to become the drama’s main theme, capturing its emotional currents in a beautifully weighty way. It also marks Sung Si Kyung’s first drama OST in three years, following “For A Long Time” from the 2022 series 'Curtain Call,' drawing significant attention from both the industry and fans.

Given that he handled the vocals, composition, and production, expectations are rising for what many anticipate will be one of his most standout OSTs to date. Over the years, Sung Si Kyung has reaffirmed his status as an OST powerhouse with unforgettable hits such as 'Scent of Love’s “Hee Jae,” 'The World They Live In’s OST “A Lingering Love,” 'Secret Garden’s “You Are My Spring,” My Love From the Star’s “Every Moment of You,” and 'Love in the Moonlight’s “Fondly, Goodbye.”

With Park Seo Joon and Won Ji An leading 'Surely Tomorrow,' Sung Si Kyung’s “On Some Days, With Some Feelings” is poised to heighten the drama’s emotional impact and charm as one of the most anticipated titles of the second half of 2025.