“She went home with a doll to get the sense of… you know, trying to physically make cups of tea when you’re holding something all the time. That’s a key physical thing.
“The emotional stuff, she’s got the empathy and she could smell it out herself.”
The End We Start From’s stunning first act explores how a real-life climate crisis might transpire, from a terrifying flood in London to a frenzied fight for food rations.
Although real babies were used in key scenes, thankfully Belo kept them away from the film’s more high-risk environments.
“In many ways, the babies were very clear of any stressful, high-danger situations,” she said.
“But the babies in themselves were quite challenging. You only get 20 minutes at a time with them, but they’re so integral to each scene.
“So that affected our schedule in a massive way. But the heightened parts of it, we managed, generally, to do without the babies.
“And we found ways to shoot it cleverly so we didn’t have to use them in any huge bits of danger.”
The End We Start From is out in UK cinemas on Friday, January 19.