Oscar Isaac and Jessica Chastain both graduated from the same Julliard class and have been friends for over 20 years.
Jessica Chastain said her one condition for going fully nude in the series was that Oscar Isaac had to strip totally naked too. Isaac agreed but didn't realize how much of his body the camera exposed until he saw the episode.
Michelle Williams was originally cast in the lead role opposite Oscar Isaac but dropped out. Isaac's good friend, Jessica Chastain replaced her. This is the second collaboration between them after playing a married couple in A Most Violent Year (2014). (Incidentally, the reverse situation happened on A Most Violent Year, where Chastain recommended Isaac to replace Javier Bardem, who was originally cast in the less of that film).
This five-episode miniseries is a remake of a six-episode miniseries. The second episode of the original is skipped, and the remaining five episodes are broadly preserved, with some changes.
The characters in this remake have similar names to their counterparts in the original Swedish version: Jonathan (from Johan), Mira (from Marianne), Ava (from Eva), Kate (from Katarina), Peter (also Peter in the original), and Poli (from Paula, originally a woman).