In the web drama "Sound of Heart," fans have spotted Lee Kwang Soo and Song Joong Ki working together. The users on online communities and SNS recently spread the word that both Lee Kwang Soo and Song Joong Ki were spotted filming somewhere in Seoul.

Song Joong Ki was joining in the last filming of new KBS2TV's web drama "Sound of Heart." Though he has his busy schedule, he decided to support the male character of the drama, Lee Kwang Soo by proving his loyalty and love for his best friend and making an appearance together.

Lee Kwang Soo made an appearance together for Song Joong Ki's drama, "Descendants of the Sun." The role of a webtoon writer will be played by the actor of The Descendants of the Sun, in the 31-year-old actor's KBS 2TV's show, The Sound of Your Heart. 

The web drama "The Sound of Heart" is based on a webtoon title "The Sound of your Heart." The web drama deals with various stories of the cartoonist, Jo Suk's real life and the people around him, which include his older brother Jo Joon and his girlfriend-turned-wife, Ae Bong. Lee Kwangsoo plays the male lead character. The other casts include Jung So Min (Ae Bong), Kim Dae Myung (Jo Joon), Kim Byung Ok (Jo Suk's father), and Kim Mi Kyung (Jo Suk's mother).

There are ten episodes in "The Sound of Heart" with duration of 10 minutes each in every episode. The drama is produced by Cross Pictures, directed by Ha Byung Hoon, and written by Jo Suk and Lee Byung Hoo.

Lee Kwang Soo had also supported his best friend by making an appearance together in episode one of "Descendants of the Sun." He proved the strong friendship by cheering on Song Joongki by coming to his fan meet event in Seoul.