“Sorry! Love and many hugs,” it added.

He checked the email, which said in part: “This is the last thing you needed, but I’m afraid the coronavirus situation is rather worrying.”

It was the last thing he needed. His reaction: A simple “Er, thanks, Mum.”

But Mr. Hulbert said that text was the main moment he realized that making a film about people hiding from a life-threatening disease had suddenly collided with a real-life event: the fast-spreading and dangerous coronavirus outbreak.

“It’s certainly been strange,” Mr. Hulbert said in a telephone interview on Friday. “This synergy between what we’re working on and what’s been happening in the world, with the quarantine line getting closer.”

“It’s obviously incredibly tragic,” he added about the outbreak that has swept into 56 countries, infected more than 83,000 and killed over 2,800. “But it’s certainly been very helpful for the actors to draw on, I think.”

The actors would all discuss it over the table at lunch, he added. “I look up and someone’s looking a bit worried and you don’t know if they’re getting ready or they’re freaking out a bit,” he added.