A star-studded viral marketing stunt? This is “How It’s Done.” KPop Demon Hunters stars Rei Ami and Kevin Woo surprised fans with a concert from atop a double-decker bus in New York City on Saturday, August 23.

"KPop Demon Hunters" fans were in for a major surprise Saturday when cast members Rei Ami and Kevin Woo popped up in NYC and led a sing-along to "How It's Done," the intro song to the Netflix hit. The surprise performance was part of a series of "K-Pop Demon Hunters Golden Weekend" events.

KPop Demon Hunters Sing-Along, a full-length sing-along version of the hit film KPop Demon Hunters, is coming to Netflix on Monday, August 25. The release of this new version follows the one-weekend-only, limited theatrical sing-along screening event in 2,180 theaters in the US, Canada, UK/Ireland and Australia/New Zealand.