The last two members of K-pop superstars BTS to enlist for mandatory military service, Jimin and Jung Kook, were set to begin their training on Tuesday, South Korean media reported, resulting in the entire mega group being on hiatus.

All able-bodied men in South Korea must serve at least 18 months in the military. 

After a years-long debate about whether BTS deserved a rare exemption, Jin, the oldest member of the group, enlisted last year, with the remaining members following suit in 2023.

The BTS septet has become a global cultural phenomenon, selling out stadiums around the world and dominating key US charts while raking in billions for South Korea's economy and building an international legion of fans known as ARMY.

BTS members J-Hope and SUGA enlisted earlier this year. Two more members, RM and V, enlisted on Monday.

Now, the final two members of the group will begin their five-week basic training at an army boot camp on Tuesday, the Yonhap news agency reported.

"I think I will be able to rely on Jung Kook a lot since we are enlisting together," said Jimin during a livestream with fans on the web platform Weverse late Monday.

"I'll be back after doing a good job," he added.

During an earlier live stream, Jung Kook thanked his fans and said he had led a "busy life".

BTS's label BIGHIT MUSIC confirmed in November that the last four members of the group would enlist, but did not disclose additional details.

Earlier this year, the chairman of the BTS's agency, Bang Si-hyuk, said that making the band do military service was slowing down the global growth of K-pop.

South Korea offers exemptions from military service to some individuals, including Olympic medal-winning athletes and some classical musicians, but K-pop stars are not eligible under the existing program.

And in an intensely competitive industry where artists can be easily replaced, some male K-pop stars have faced challenges in resuming their careers after fulfilling their duties.

BTS's agency HYBE announced in September that all seven members of the group had renewed their contracts, without giving further details.

The announcement implies that all seven members are likely to stay with the agency after completing their military service.