The skit, released on Monday, features Fallon contacting Colbert as the duo prepare for new episodes of their respective shows.
Fallon and Colbert then launch into a rendition of NeverEnding Story from British singer Limahl.
The moment is reminiscent of a popular scene from Stranger Things Season 3 featuring Dustin (Gaten Matarazzo) singing the song with his girlfriend Suzie (Gabriella Pizzolo).
Fallon's Tonight Show announcer Steve Higgins walks in on the performance and gives him props for referencing the supernatural drama.
"Why was he talking about Stranger Things?" Colbert asks.
"I don't know. Never seen it," Fallon replies before continuing to sing.