BTS member Jin bids farewell in Buenos Aires ahead of mandatory military service

The K-pop star performed new single 'The Astronaut' with Coldplay in Argentina

Fans of BTS unable to attend the concert gather outside the Monumental Stadium, Buenos Aires, to listen to Jin perform his single 'The Astronaut' with Coldplay. All photos: AFP

Fans outside the stadium for Coldplay's concert in Argentina.

A fan holds up a sign in Korean for BTS member Jin.

BTS fans queue to access to River Plate's Monumental stadium to attend the fourth of 10 concerts from Coldplay in Buenos Aires.

A BTS fans holds an image of Argentine footballer Lionel Messi, left, with BTS member Jin.

A fan holds up a sign in Korean for Jin ahead of the Coldplay concert.

A fan has a sign asking Jin to marry her.

Fans in Argentina show their support for BTS.

Fans hold up photos and posters for Jin.

Argentinian fans of Jin pose with a flag made specifically for him.

BTS fans show off their signs ahead of the concert.

BTS fans wear Argentina's football team shirts, with one specifically for Jin.

Thousands of Argentinian BTS fans were moved to tears as they said goodbye to K-pop superstar Jin on Friday. He performed his emotional new single The Astronaut alongside Coldplay as he prepares to take a hiatus to complete mandatory military service.

"We didn't have time to do anything. He arrived, he sang, we cried and we didn't even realise he was leaving," Eliana Suarez, a law student, 25, said at the end of the concert at the Monumental Stadium in Buenos Aires.

"It's magic that he comes to Argentina, that he chooses Argentina to sing his single," she said, adding that it was "very emotional".

The singer, 29, performed his song, co-written with singer Chris Martin, on Friday during one of Coldplay's 10 concerts in Buenos Aires, part of their Music of the Spheres tour.

"It was the best thing I've ever seen, the most spectacular, the best show. I grew up with Coldplay ... and now BTS." said Daniela Zuniga, 21, who is a medical student.

The announcement of Jin's participation in Coldplay's concerts in Buenos Aires had triggered a frenzy.

Hundreds of women, often wearing the purple dresses of BTS fans, camped out for days in front of the stadium to get a seat.

"A lot of people were left without tickets, there are a lot of resales and a lot of scams. They took advantage of the desperation," Noelia Zarate, 23, who makes T-shirts embroidered with K-pop designs, said.

With the 600,000-capacity stadium full, a few hundred fans who could not get tickets watched the concert from outside.

On Twitter, the hashtags #TheAstronaut and #ThanksArgentina, the phrase with which Jin bid farewell to the audience, were the two main trends on Friday.

A fortnight ago, the agency representing BTS said the band's seven members would enlist in the military, putting an end to a debate about whether they should be exempt from the mandatory service requirement of about two years.

Jin, the eldest of the septet, said he would sign up in December.

The group, credited with generating billions for the South Korean economy, have said they hope to reconvene by 2025.

Scroll through the gallery below to see BTS through the years.