The makeup artist Frederica was 16 at the time of production, and had never done any makeup for film before. She learned from watching YouTube videos.
All of the visual effects were created by Drew Casson, who was aged 19 at the time of production.
The flat that the characters live in was actually the home of Sam Carter (who plays Kipper) at the time of shooting.
Cowen and Phil played by Drew Casson and Georgia Bradley got together during the course of production and are now a couple in real life.
Cowen and Adam are played by real life cousins Drew Casson and Tom Scarlett.