Dynamite, the first song by South Korean boy band BTS to be sung entirely in English, will drop on Friday (Aug 21).

As with anything to do with the world's biggest boy band, excitement has reached fever pitch and reactions have been explosive.

On Tuesday, the seven-member group released a teaser clip for the music video on YouTube and it has already racked up more than 40 million views.

In a interview with American newspaper USA Today, the group, through an interpreter, shared the story behind Dynamite's production.

They said stepping out of their comfort zones to sing in English took some getting used to, especially getting the pronunciations down.

"It was not hard but interesting. It was an interesting kind of challenge," member Jung-kook says. Nam-joon, better known by his stage name RM, noted it was "fun hard".

The group, which debuted in 2013, said creating the song was "like destiny".

Nam-joon says: "Who would ever think of this pandemic? No meeting, no karaoke, no concerts? Even no walking in the park. So we never expected this song would come fully in English. During the process of making our album… it just came to us."

Yoon-gi, who goes by the stage names Suga and Agust D, added that the pandemic is "a situation that everybody else around the world is facing, so we just started to explore what can we do right now, what can we do really good?"

When they announced the release of Dynamite in July, BTS said: "When we first heard and recorded the song, we were energised and our spirits were lifted up."

When asked during the USA Today interview if the group have plans to release more music in English, Tae-Hyung, better known by his stage name V, said: "Don't not look forward to it."

Watch the teaser to Dynamite here.