SEOUL, South Korea (AFP) — South Korean megastars BTS performed their first show in nearly four years on Saturday in front of enormous crowds in Seoul for a K-pop extravaganza livestreamed to millions more worldwide.

Widely lauded as the biggest boy band in the world, BTS went on hiatus in 2022 so the seven members could serve compulsory military service, some near the heavily fortified border with North Korea.

The comeback concert had as its backdrop the historic Gyeongbokgung royal palace — fitting for the “Kings of K-pop” — with thousands of fans from South Korea and abroad singing along.

“It’s been a long journey but now we are finally here!” said BTS’s leader RM — whose injured ankle meant he had to perch on a stool at times — as the group performed songs from their new album, as well as old hits “Dynamite” and “Mikrokosmos”.

“We are finally here and seeing you again… all seven of us standing on the stage together makes me so happy,” said fellow member Jimin to cheers.

“BTS 2.0 is just getting started,” said J-Hope.

Fans — 260,000 were predicted earlier — descended on Seoul from morning onwards in colourful costumes, taking selfies with their tickets and clutching BTS “ARMY” glowsticks.

Before they came on stage the crowd chanted “BTS! BTS!” with the main boulevard leading up to Gwanghwamun Square ram-packed with people as far as the eye could see.

Gwanghwamun Gate was lit in rainbow colours before the show started, as a massive stage installation featuring three circular features — symbolising BTS’s new album “Arirang” — glowed beneath towering lighting rigs.

The megastars admitted to some nerves, with member J-Hope telling fans “there were moments when we wondered whether we might be somewhat forgotten, or whether you would remember us”.

Jimin said: “We are not such special people. We are afraid every time, but we believed that if we showed you our sincerity, it would reach you.”

Fans responded with a sea of glowsticks, singing along the songs while holding their phones high up to film their stars.

“It’s great that the show was held in Gwanghwamun, but it would have been just as good anywhere — even in a much smaller venue,” Park Young-mi, 34, a South Korean fan, told AFP.

“Fans have been waiting unwaveringly, and I hope they felt that today.”

“Seeing them on stage just felt as if I was being welcomed into a family… it felt very expressive and beautiful and you could just see it from the people who were here too,” gushed Gabriel Miranda, 34, from the United States.

“It’s a bit different from BTS’s usual flavour, but seeing this new side of them at this historic place is deeply moving,” said Jo Jung-hee, 60, her phone featuring a photo of BTS member V.

Millions more people across the world were able to watch the show broadcast live on Netflix.

The latest album, “ARIRANG”, which was released on Friday, is billed as a reflection of the maturing boy band’s Korean identity.

It sold almost four million copies in the first day, BTS’s record label said.

Spotify said five million fans pre-saved it, the highest ever for a K-pop act, and that it was the most-streamed album in a single day so far this year.

“ARIRANG” takes its name from a folk song about longing and separation that is often dubbed South Korea’s unofficial national anthem.

Featuring collaborations with multiple Western artists and producers, the 14 tracks on the album mix rap, heavy beats and experimentation.

“Compared to their earlier work, there’s a wider range of genres, which gives it a more mature and expansive feel,” Lee Ji-young, a university professor, told AFP.

– Taylor who? –

Saturday’s show preceded a world tour set to be a major money-spinner for BTS, potentially outdoing Taylor Swift’s recent Eras Tour.

South Korea too — whose music, films, books, food and cosmetics are all the rage — will benefit thanks to tourism and sales of merchandise from BTS dolls to toothbrushes and cans of tuna.

Starting in Goyang, South Korea on April 9 and ending in Manila 11 months later, BTS’s tour encompasses 82 shows in 34 cities in 23 countries.

Security was heavy for Saturday’s concert, with some 15,000 police and security guards, barricades lining the roads and local venues shut.

Wedding guests had to be transported by police.

BTS — short for Bulletproof Boy Scouts in Korean — have championed UNICEF campaigns, the Black Lives Matter movement and efforts to combat anti-Asian racism.

Members have also spoken candidly about the pressures of the music industry.

“Honestly, I became a fan simply because I love their music,” Seo Ra-jung, 40, told AFP after the concert.

“I first became a fan during a really difficult period in my life, and their lyrics gave me a lot of strength.”