Here's Billie Eilish's head-rotating performance of 'Bad Guy' on 'SNL'

Spoiler: Billie Eilish is not able to walk on walls.

If the camera effect on show during Billie Eilish's performance on 'SNL' looks familiar to you from the likes of 'Inception', you're correct.

The process involves fixing a camera to a rotating set and then manually moving the entire set like a hamster's wheel. The camera, because it's stationary and rotates with the set, makes it seem like the movable object inside - Billie Eilish, in this case - is able to walk up walls.

The camera trick has been used countless times in the likes of '2001: A Space Odyssey', 'Poltergeist', 'Nightmare On Elm Street' and, more recently, 'Inception'. In that instance, a huge set was built that was nearly 30 feet wide and 120 feet long to replicate a hotel corridor.

This time around, however, it's Billie Eilish on the 'SNL' soundstage with two stagehands rotating the set.

Take a look.