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.

The Netflix production KPop Demon Hunters is being showcased in theaters for a limited weekend, featuring sing-along sessions. In a delightful surprise for fans in New York City, the voice actors of the beloved characters took to a double-decker bus to perform several of the songs.

The sing-along version of the Netflix film topped the box office this weekend, grossing an estimated $18 million to $20 million.