Clooney cast the Brit as an astronaut in the Netflix film he directs and stars in weeks before she realised she was pregnant, and when she told him, he eventually decided to incorporate her real-life story with the one in the film.
"Wilber (son), while he was still in the womb, really was a character suddenly," Clooney tells Deadline. "He became somebody that was important to all of us."
"The first thing you do is go, 'Great. I'm thrilled for you'. Now it's (your pregnancy) a problem for us and we're going to have to solve it. The way we tried to solve it initially was by pretending it didn't exist. Like shooting her from the neck up and doing body doubles and all that kind of stuff. On top of it being really tedious, it was draining the life out of the scenes."
"We're shooting scenes three times and she wasn't comfortable with it because she was trying desperately to hide it, and she was showing pretty good at that point."
Clooney then had a moment of clarity and decided there was no reason for Jones' character not to be pregnant too.
"I woke up in the middle of the night and I just said, 'People have sex'," he recalls. "That's what happens on two-year trips, and then I sort of pitched it to Felicity as, 'Think of Frances McDormand in 'Fargo', where there was no real reason for her to be pregnant. That wasn't a real storyline...' Pregnant women do go to work every day, they do all of these things and they sort of never get represented."
"I said, 'Let's just make her a pregnant astronaut'. Then, as it went on, we had to start writing scenes to introduce that. It started to become really clear that little Wilber there was so important. He was the future and we were to guard him really carefully."
Jones' pregnancy prompted Clooney to rework the ending of the film, and now he insists, "It ended up feeling as if it should have been in the script all along."