A livestreamed comeback concert by K-pop megastars BTS drew 18.4 million global viewers on Netflix, according to the streaming service.

Saturday's one-hour programme marked the first time all seven members - Jin, Suga, J-Hope, RM, Jimin, V, and Jung Kook - have performed together since October 2022, when they went on hiatus to complete their mandatory military service.

The free concert, staged at the historic Gwanghwamun Square, was attended by about 104,000 people, according to entertainment company Hybe, which is lower than the 260,000 anticipated by authorities.

Hybe's shares had risen in recent months ahead of the comeback tour and the release of their new album Arirang, but fell by 15.5% on Monday.

The event marked the start of the band's sold-out, 82-date world tour and was livestreamed on Netflix to more than 190 countries, including South Korea.

Just around 22,000 people secured free tickets for the main concert venue, while other spectators watched the performance on a dozen screens set up along nearby streets.

The concert prompted the government to deploy about 7,000 police officers, including SWAT units equipped with anti-drone systems, to maintain order.

The broadcast topped Netflix's rankings in 24 countries, the company stated.

This concert showcases Netflix's growing ambition in live event broadcasting, following other high-profile events that have drawn significant viewership.

BTS and their record label BigHit, along with Hybe, are projected to generate over $1 billion from their reunion through concerts, merchandise, licensing, and album sales, according to Billboard.

BTS remains a crucial income source for Hybe, especially during the periods of their absence from the public eye.