Even weather reporters are reliant on this technology to point to the map as though they were floating above the Earth.

But when chroma keying was first used in 1940 by Larry Butler on The Thief of Baghdad, the green screen was originally blue.

Realistically, either colour works because they are far away from skin tones, making it easy to replace the background without accidentally removing a part of the actor’s face.

Green screens can be made from cloth or paper, but whichever you choose, you must make sure it’s 100% wrinkle-free – a process which can take around two hours!