BTS will perform for free to support South Korea's quest for the World Expo.

For the concert, dubbed "BTS in BUSAN," around 100,000 fans from all over the world are anticipated in Busan.

The international megastars are credited for helping to boost the South Korean economy by billions.

Aside from music, the band has supported progressive issues around the world, including as the Black Lives Matter movement and the fight against anti-Asian prejudice in the US.

The celebrities were chosen by the government to serve as the official ambassadors for Busan's bid to host the World Expo in 2030 about a month after that announcement.

According to the organisation in charge of organising the expo, the South is one of four nations that have submitted a bid to host the event, along with Saudi Arabia, Ukraine, and Italy.

BTS may be permitted to continue performing and practising for international concerts even as they are on active duty, according to Seoul's defence minister in August.

The concert is taking place after the septet dropped a bombshell announcement in June that they were taking a break as a group to pursue solo projects.