JYJ Junsu's OST for drama 'Heaven's will' will be released today.

Titled "Foolish Heart," the soundtrack became the most searched term online in Korea upon its sneak pre-release during an episode of 'Heaven's Will' last week.

Themed around the tear-jerking love story between Lee Dong Wook and Song Ji Hyo, the song contains everything from the subtleties of romance to the fragility of the human heart.

"Foolish Heart" was composed by Wi Jong Soo and written by Kang Woo Kyung.

The production company of the OST stated, "JYJ Junsu poured his heart out for the recording of this song and participated in the mixing work near the end of the song. He showed a lot of dedication and passion for this work. All the staff members were very impressed by what he did."

This is JYJ Junsu's third time working on an Original Soundtrack for a KBS drama. His previous works were in 'Sungkyunkwan Scandal' and 'The Innocent Man' both of which were successful.

"Foolish Heart" will be officially released at noon on May 15 in Korea.