Singer Jeon Geon-ho revealed his identity through a battle with the reigning champion "Perfect Shot Marksman" on MBC's entertainment show "King of Mask Singer." In the 517th episode aired on November 2, masked singers competed in solo song battles. Jeon Geon-ho appeared wearing the mask "Autumn Post Office" and showcased his vocal skills.

On this episode, Lim Han-byul mentioned about "Autumn Post Office," saying, "A singer who was a candidate for first place on music shows alongside IU and IVE." He explained that Jeon Geon-ho has experience remaking songs by Ivy, VOS, Buzz, and others, and that the related music video recorded 14 million views. Kim Gu-ra speculated, "Seeing that he has done many covers, he seems to be a strong digital music player whose face is not well known."

Jeon Geon-ho postponed revealing his identity by advancing to the third round. Instead, the unmasked "Fig Cake" was revealed to be Jung Daehyun of B.A.P. Jung Daehyun made a comeback last year as a unit with B.A.P members after about six years, and this time shared news of releasing a solo song. He said, "I want to meet fans on many stages such as busking and festivals in the future."

In the battle between "Quack Quack Duck" and "Teto Girl," "Quack Quack Duck" won. The identity of "Teto Girl" was confirmed to be Jung Yoo-kyung, the vocalist of the 1990s co-ed group Rumors. Jung Yoo-kyung expressed gratitude for the much love received despite Rumors' short activity period. She is currently active as a musical actress and trot singer and stated her goal to build a diverse career.

In the third round, the child masked singer "Quack Quack Duck" captivated the audience by passionately singing IU's "You and I." However, due to a delay in recording time, they had to leave early. "Autumn Post Office" was selected as a finalist for the king's decision match. The identity of "Quack Quack Duck" was revealed to be Lee Soo-yeon, an 11-year-old born in 2014. Lee Soo-yeon said, "I was so surprised and honored to make it to the third round. I want to win first place many times in the future and be filial to my grandfather and grandmother."

In the king's decision match, "Perfect Shot Marksman" won a second consecutive victory by passionately singing The Black Skirts' "As Much as I Waited." The unmasked "Autumn Post Office" was confirmed to be Jeon Geon-ho. Kim Gu-ra expressed delight, saying, "It's a song I like, and he sang it a lot here." Jeon Geon-ho shared his thoughts, "I rose steeply and didn't have enough time to adapt. It was the first time I was impressed by myself while singing." He expressed his aspirations, saying, "Appearing on the famous 'King of Mask Singer' has made me more recognized. I will show you many better songs in the future."