This past February, K-pop group BTS took the Grammy Awards by storm. It was their debut at the award show, and their nomination — for Best Recording Package — marked the first time a Korean record was recognized by the Grammys. BTS arrived on the scene in coordinated tuxedos and broke the internet with their first steps out of the limo.

But a day before the Grammys, the group was preparing for a record-breaking Entertainment Weekly cover. They were about to let a journalist into their top-secret recording studio in Seoul, and they convened in Los Angeles for a photo shoot to kick things off.

Image zoom Peter Yang for EW

The production went down at a secret location (all we can reveal is that it was a hotel), and security was tighter than perhaps any EW cover shoot before. BTS — comprised of members RM, V, Suga, Jin, Jimin, Jung Kook, and J-Hope — brought an ARMY-sized entourage with them, including an interpreter and several high-level staffers at Big Hit, the prestigious K-Pop entertainment group. The group was so large that EW’s producers had to hunt high and low for furniture to accommodate everyone (you can see the special seven-person-sized couch in the video interview above).

But all the pomp and circumstance did nothing to hinder the enthusiasm of BTS: They were laid-back and casual at the photo shoot, despite their trans-Pacific-flight-induced jet lag. Just like any twenty-something friends, they were goofing around and singing top 40 songs in between takes (Ariana Grande’s “7 Rings,” to be exact). And, at EW’s request, they even took some time out to teach us their favorite Korean slang.

The Grammy weekend photo shoot was just the beginning of preparations for EW’s landmark cover: A few weeks later, Leah Greenblatt flew out to interview BTS in Seoul, South Korea. She is the first Western journalist to be allowed into the group’s recording studio and was given unprecedented access.

Greenblatt toured the facilities, spent time watching the group prepare the finishing touches on their soon-to-be-released album Map of the Soul: Persona, and even listened to a track off the highly-anticipated EP. Oh, she also bore witness to the sheer scope of the band’s hometown fandom — including, but not at all limited to, the dedicated billboards that members of ARMY purchase to honor their favorite members.

Check out the full cover story now — and stay tuned for even more exclusive access to be revealed.

For more on BTS, pick up the new issue of Entertainment Weekly on stands Friday, buy it now, or scoop up our limited-edition BTS poster. And don’t forget to subscribe for more exclusive interviews and photos, only in EW.