Speaking about the film’s origins, Pete Docter, the director of 2001’s Monsters Inc, said on Jeff Goldsmith’s Creative Screenwriting podcast: “Well, my idea was that what it was about was about a 30-year-old man who is like an accountant or something.

“He hates his job, and one day he gets a book with some drawings in it that he did when he was a kid from his mum, and he doesn’t think anything of it, and he puts it on the shelf and that night, monsters show up. And nobody else can see them.

“He thinks he’s starting to go crazy; they follow him to his job and on his dates, and all this – and it turns out these monsters are fears that he never dealt with as a kid.”

A bit like fellow Pixar hit Inside Out, which includes personified emotions, each of these monsters would have represented a different one of the office worker’s fears.

As soon as he was healed from one of the fears these monsters symbolised, it would go away. This was actually a little bittersweet, as the original plot’s main character grew close to some of his new companions.

While I have you, here’s another fact about the first movie: Boo actually had a real name all along. Eagle-eyed fans spotted a detail suggesting she was called Mary, like the child actor Mary Gibbs, who voiced her.

Real-life Mary has since voiced characters in Inside Out, though she was only two years old when she starred in Monsters Inc.