https://www.digitalspy.com/tv/a28948563/netflix-the-crown-gillian-anderson-margaret-thatcher-season-4Makes perfect sense - they could be sisters:
I liked this tweet:
@roisincaird
·Very much looking forward to being able to use the line "I haven't felt this sexually conflicted since they cast Gillian Anderson as Margaret Thatcher in The Crown".
(mind you , Helena Bonham Carter as Princess Margaret presents a similar problem ...