On August 29th, 'Idol Champ' shared a voting poll for a subway station ad for idols who are born in October on their official Twitter account. The voting took place in their official application. The voting poll consists of preliminaries round and finals round. Idol Champ also shared a list of idols who were included in the voting poll.
On September 5th, BTS's Jimin made it to the final round when Idol Champ shared the top 5 idols who made it to the final round via Twitter. Finally, on September 16th, BTS Jimin was announced as the winner.
Congratulation BTS Jimin.
Check out the advertisement for BTS Jimin by Idol Champ.
Source
Its Jimtober ✌❤