NEW YORK, NY - MARCH 02:  Actor Noah Schnapp and Panic! at the Disco singer Brendon Urie perform at Madison Square Garden on
B51-Mark Brown/WireImage

Panic! At the Disco fans were in for a fun surprise during last night's concert at Madison Square Garden, where the band brought Stranger Things star Noah Schnapp on stage. The buddies came together to sing along to "L.A. Devotee" off Panic!'s GRAMMY-nominated Death of a Bachelor album.

The crowd went wild as Schnapp adorably hopped around stage while performing the track alongside frontman Brendon Urie. The actor shared a photo from a few moments before he went on stage with the funny caption, "I look like I just saw the demogorgon." Schnapp was the main star in last September's twisted video for "L.A. Devotee", where he was inducted into an underground Los Angeles cult. 

Panic! kicked off their Death of a Bachelor Tour with special guests MisterWives and Saint Motel on Feb. 24. The band will wrap up the trek on April 15. As for Stranger Things Season 2? Look out for its Netflix return on Halloween. Check out some fan-shot footage from the MSG show below:

Next up, flip through our list of things we need to see in the new season and watch Brendon Urie discuss how he called his own shots on Death of a Bachelor with Fuse: