But it’s not the only headline-making relationship in the show. Elizabeth and Margaret get plenty of airtime too. Episode one opens in 1979 with the arrival of a new Prime Minister, Margaret Thatcher. The role is played by Gillian Anderson who is quite superb in her portrayal.
She has the voice and that distinctive Thatcher walk - sort of bent forwards and always in a hurry - down perfectly.
Her first audience with the Queen presents them as opposites - although both female leaders, Thatcher is the self-made daughter of a greengrocer who’s had to work every step of the way; the Queen has become a leader through birthright.
Comparisons and metaphors abound - in one episode Mrs Thatcher’s son Mark, while competing in the Paris to Dakar rally, gets lost, but the Queen’s children are lost too - Anne in an unhappy marriage, and Charles, forced to relinquish the woman he loves to marry Diana Spencer, is portrayed as a broken soul.
When Diana is on screen the soundtrack is pure 80s pop gold; for Charles and his family it’s classical. Two worlds, out of sync.And so to Diana. Relative newcomer Emma Corrin spent months preparing to play the once most photographed woman on earth.
And it has proved to be brilliant casting.
She perfectly captures Diana’s breathy voice and pronunciation, that tilt of her head, the ready blushes - it’s quite uncanny.
Famous scenes are reconstructed - the bride-to-be pursued down the road by photographers; wading through reporters outside her Earls Court flat; the engagement announcement when Charles famously responds to a press question asking if the couple are in love, with “whatever love is”.
Like lambs to the slaughter, you can’t help screaming “don’t do it” to both of them.
Where Diana is shown as an innocent simply seeking a fairytale love, Charles is the tortured man torn between duty to the Crown and to his own true love.
His relationship with Camilla Parker Bowles features strongly, their secret liaisons and Diana’s anguish over their continued affair.So much has been written about the “three people in this marriage” set up, with Charles’ supporters and Diana’s camp vying for column inches in later years.
The Crown paints Charles as a victim too, and there is much to pity in this series, but on measure I’d say it comes down more sympathetically on the side of Diana.
There are uncomfortable scenes depicting her eating disorder bulimia in which she is seen bingeing on food in stressful moments, and then forcing herself to be sick, scenes which are shocking and carry a warning at the start of each episode.
The royal family is shown as cold towards her, Charles as jealous of her popularity, her turning to lovers like Major James Hewitt as inevitable in response to Charles preferring Camilla.You couldn’t make it up, but then you don’t need to.
Watching The Crown you are reminded how much like a soap opera the royal story is, albeit played here with dramatic licence.
Prince Andrew pops up, a Falklands hero, all arrogant and cocky. Little wonder the drama will stop after two more series before the storylines involving him, get too murky and legally challenging.
As ever the series is a triumph of casting.
Let’s hope Prince Charles doesn’t watch The Crown as it won’t be comfortable viewing for him, but at least he might be able to take some solace in how Josh O’Connor plays him.
He is even better than in series three, capturing the voice and awkwardness perfectly.
When he and Emma Corrin are on screen, the series is at its most powerful and moving.
We don’t get into the later years and Diana’s interview with Martin Bashir, now marking its 25th anniversary.
That will come in series five, when Diana will be played by Elizabeth Debicki and Charles by Dominic West. Imelda Staunton will play the Queen as she experiences her “annus horribilis”. Series four then, released on Netflix on 15 November, is almost the calm before the storm.