In a recent interview with Vulture, she revealed that she was able to overcome her nervousness with the help of some liquid courage and a private concert from Isaac.
Chastain explained that Isaac, a good friend of hers for over twenty years, played some music and they drank a bit of bourbon together to calm her nerves. He even sang a song she really likes in between takes to lighten the mood.
Despite their long friendship, the scene was still quite awkward for both of them, as they had to follow instructions from an intim-cy coordinator to make the movements look more realistic.
Chastain found that the key to making the scene work was to focus solely on Isaac, to lock eyes with him and to try and convey the love they share onscreen. She believes that this chemistry was made more authentic by their long-standing friendship, but that didn't make the process of filming the scene any less uncomfortable.
All in all, it seems that the onscreen chemistry between Chastain and Isaac is the result of a lot of hard work and a close friendship.
