Gwyneth Paltrow was sick during the filming of Iron Man 2. Some subtle tells were that her face and makeup coloring are a little off, and for some of the scenes, her voice is a little nasally… probably due to congestion.
She did a great job of toughing it out and hiding it.
An example I actually got to see in person was Linda Cardellini on an episode of ER back in the day.
I have all the respect in the world for this actress. She was sick as a dog… I’m talking full-on viral cold. Heavy duty mucus, fever, coughing… it was a miracle she was on her feet. But the show must go on, and damn… she is a TROOPER. If that had been me, I’d been in bed for a week and not come out of my cave till I was better. And yet, there she was, churning through her lines and just trying to survive the day.
We had to wheel in a gurney and in between takes she’d need a minute to rest her head on her hands. It’s one of the few times I spoke to a lead actress on set without being prompted, just to make sure she was okay and to ask her if she needed anything.
To hide the cold, she was under some pretty heavy makeup and the director was primarily shooting the scene from behind and over her shoulder. If you listened to her, you could hear a bit of a chest rattle as she talked and her voice wasn’t quite as high as it normally is, it was sitting a little lower in her register.
I didn’t really know anything about her before that day, but I learned everything I needed to know in about ten seconds of seeing her that sick. This woman has some serious work ethic and character!