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” fever is gripping New York, with the stars of the wildly popular animated Netflix film lighting up the Empire State Building on Friday. The movie, which premiered on Netflix in June, quickly became a blockbuster hit around the world, with the streaming giant now releasing a sing-along version in Big Apple theaters this weekend.

The Netflix feature KPop Demon Hunters is in theatres for a special weekend with sing-along screenings. The actors who voice the popular characters surprised fans in New York City as they hopped on a double-decker bus to sing some of the songs.