ILIT members Yoona and Minju are taking on their first-ever OST since debut.

The two participated in "I Thought of You All Day the Moment I First Saw You," the fourth OST for KBS2's weekend drama Last Summer (written by Jeon Yu-ri, directed by Min Yeon-hong).

The medium-pop track captures the youthful excitement of falling for someone at first sight. Yoona and Minju bring a soft, airy tone that adds vibrancy and warmth to the song.

Producer Song Dong-woon led the production. He previously shaped the hit Goblin soundtrack, including "I Will Go to You Like the First Snow," "Stay With Me," "Beautiful," and "I Miss You."

ILIT has been active in the soundtrack scene recently. As a group, they also recorded the OST for the Japanese TV animation It's Time for Princess Torture Season 2, scheduled for release in January next year.

Last Summer is a "remodeling romance" drama that follows two childhood friends uncovering the truth behind their long-hidden first love.

"I Thought of You All Day the Moment I First Saw You" will be released today at 6 p.m. on major music platforms.