The 32-year-old actress stars as the late royal – who famously wore a short black dress to a dinner at the Serpentine Gallery in Kensington Gardens following her husband King Charles’s admission of adultery – in the biographical Netflix series and described the event as a “powerful sartorial” moment in fashion history.
She said: “We all felt the responsibility of the revenge dress because it's something that everybody wanted to see. It’s an incredibly powerful sartorial moment in the history of fashion.
“That dress is so emblematic of so many things because it’s so brave and beautiful, but it's also so tinged with our understanding of what was going on in this person’s life.
“So the duality of that is really powerful, I think, and we really felt that we had to do it properly.
The “Great Gatsby” star went on to describe the Christina Stambolian dress worn by Diana – who was killed in a car crash in 1997 at the age of 36 just one year after divorcing from the then-Prince Charles – as “powerful” and will “never forget” the day on set.
She told E! News: “It’s a powerful dress. It’s a totally unique dress too — the structure of it, the shape of it, the look of it — and so I certainly won't ever forget that day on set.
“We shot it in the same location that it actually happened, so there was this slightly deep layering of things going on that day.”