The Australian actress, 33, who has played the late royal since series five of Peter Morgan’s The Crown, spoke about the experience in a behind-the-scenes featurette.
‘It’s a really unique challenge as an actor to portray those days, because we know where the story is going,’ she said.
‘It really is like a very quick follow-on in terms of the actual timeline of the story telling from season five.’
‘I don’t really know any humans who could endure that,’ Elizabeth added, remarking on the newspaper attention the couple received.
‘It was very difficult to recreate, it was very heavy, manic and incredibly invasive.’
She and Khalid ‘let themselves be present in each moment of the scene’ because so much of the story is… a lovely time’ – but takes a turn after ‘press element’ is introduced.
Khalid added that portraying the romance was a ‘huge responsibility’.
‘I hope audiences, when they see it feel that we have done it right,’ he said. ‘And honoured how sensitive it is.
‘It’s that thing that we experience with all tragedies. It’s not about you knowing the ending, you know the ending. It’s about exploring as accurately as possible – the tensions that bring you to that place.’
For this series, The Crown has recreated final moments before their fatal car crash in Paris in 1997.
In a daunting clip, shared today as the first instalment in the final season of the Peter Morgan drama is released, Diana and Dodi are shown getting into a car outside the Ritz Hotel in Paris, which Dodi owned.
Speaking in a corridor ahead of their ill-fated final journey, Dodi asks Henri Paul – the deputy head of security at the Ritz – if the pair are safe to travel.
Speaking in French, Henri explains that two staffers have taken a decoy vehicle, so the coast is clear for Diana and Dodi.
‘No one will see us leave, trust me,’ he tells Dodi.
But as the couple walk out to the Mercedes-Benz W140 they are flanked by paparazzi.
Ominous music then plays as the driver asks Diana if she’s okay, before Dodi tell Henri – driving the vehicle – ‘allez’.
The clip then cuts out before the crash.
Netflix has previously said the show will not show the crash itself, but will show events leading up to and the aftermath of Diana’s death.
The scene has Diana calling Balmoral to speak to her sons, only to be told be an aide ‘you missed them’.
The emotional first four episodes cover the tragic car crash in Paris that killed Princess Diana in August 1997 – alongside her lover Dodi and their chauffeur Henri Paul – and the Royal Family ‘s reaction to it, as well as the summer holiday Diana and Dodi enjoyed in St Tropez prior to the tragedy.
The Paris scenes were shot in the French capital, while a yacht was hired for the St Tropez scenes, although these were actually filmed in Mallorca.
For sensitivity reasons the exact moment of Diana’s death is not re-created, but there are controversial scenes in which Charles tenderly converses with an imaginary Diana in the cabin of the royal plane as he accompanies her body from Paris to London , and later when she also appears to the Queen.
Critics who have seen these scenes called them ‘farcical’ for portraying Diana as a ghost, but series creator Peter Morgan has insisted that wasn’t the intention.
‘I never imagined it as Diana’s ghost in the traditional sense,’ he told Variety magazine. ‘It was her continuing to live vividly in the minds of those she has left behind.’
The Crown was devised by Morgan after the success of his 2006 film about the Royal Family’s reaction to Diana’s death, The Queen.
And the series – which has earned 21 Emmys and dozens of BAFTA nominations, not to mention some criticism for its historical inaccuracies – covers the same ground, but using fresh information gleaned in the 17 years since the Oscar-winning movie was made.
In fact, the scripts had to be updated all the time as the Royal Family were plunged into headlines throughout the filming period, not only with the Queen’s death but also following the release of Prince Harry’s memoir Spare.