The apocalyptic Netflix movie, also starring David Oyelowo, tells the story of Augustine (Clooney), a lonely scientist in the Arctic, as he races to stop Sully (Jones) and her fellow astronauts from returning home to a mysterious global catastrophe.
Speaking in a new interview with British movie magazine Empire magazine, George opens up about the change and how it actually made the story even better.
"About three or four weeks into shooting, I got a call from Felicity," he recalls. "We started shooting the Iceland parts in October of last year, and we were going to shoot the space parts in January. She calls me and goes, 'Uhhh, I'm pregnant.' I was like, 'Oh, s**t! You're kidding!' "
Explaining he considered multiple options, Clooney continues, "The first thing we tried to do was shoot her and just do head replacement. Meaning we shoot each scene with her three times: once with her, once with a body double, and once with nothing in it. But we started looking at it and thought, 'She's not comfortable in this sort of thing.' "
"There's already enough space stuff, on wires and things. None of us felt comfortable putting her in any kind of position of stress," he adds. "Then it was really simply sitting down and going, 'Okay, so, you know, people have sex! They're going to be in space for a long time and she's pregnant.' "
"I think it ends up adding to the story, in a way," the star, who also serves as director and producer on the flick, says. "It makes it kind of beautiful by the end."