SEE ALSO: Huh Gak announces his upcoming marriage

According to a source close to the two stars, John Park will sing the congratulatory song at Huh Gak's wedding ceremony being held at The Raum at Gangnam next month. Huh Gak and John Park were rivals during their days on 'Superstar K2' with Huh Gak winning the show and John Park landing in 2nd place. But through the competition, the two developed a very tight knit friendship that still hasn't changed.

John Park's reps confirmed, "John Park will sing the congratulatory song at best friend Huh Gak's wedding. Because they normally have a close friendship, he received the request to sing the congratulatory song without any hesitation."

Huh Gak and his fiancee will be tying the knot on October 3!