Popular K-pop band BTS has announced an online live-streaming event, BTS 2021 Muster SOWOOZOO, to celebrate the eighth anniversary of the band and their fandom, known as ARMY. The two-day event will be held on June 13 and 14.

June 14 will see the 'World Tour Version' and showcase the group's foreign language songs.

Members of K-pop boy band BTS or Bangtan Sonyeondan
Members of K-pop boy band BTS or Bangtan SonyeondanBTS (Instagram)

The group made the announcement with an official poster of the event, which has the seven-member band standing together against a backdrop of nature, holding planets of the solar system on strings like balloons.

Butter video goes viral

BTS has just released their new single "Butter". The music video of the song, released on Friday, broke their own record for the biggest music video premiere on YouTube, racking up 3.9 million peak concurrents. The song has amassed over 100 million views within 21 hours.

The band's new music video also drew around 3.89 million concurrent viewers during its midnight (EST) premiere. "Butter" is also the second BTS song after "Dynamite" to be performed entirely in English, which vastly improves its prospects at radio, according to forbes.com. In its first five hours of release, the track had over 47,034,131 views on YouTube and 4.8 million likes.

"Butter" is a dance pop track with the band's distinctive baseline and crisp synth sounds. The choreography is a combination of group and unit dances, with highlight gestures such as stroking of hair, blowing kisses and walking on tiptoes.

The band will perform "Butter" for the first time at the upcoming Billboard Music Awards on May 23. They are nominated in four categories at this year's award -- Top Duo/Group, Top Song Sales Artist, Top Social Artist and Top Selling Song. The band also kicks off Good Morning America's Summer Concert Series on May 28.