It was exactly one year ago when The Crown fans got a first glimpse of Emma Corrin as Princess Diana [1]. Since then, we've all been been eager to see just how uncanny the resemblance really is between Corrin and "the people's princess." After all, Princess Diana was the most photographed woman of her time, so the pressure for visual accuracy suddenly feels more important than ever. Corrin recently told Elle [2] that she worked with a dialect and movement coach to ensure she could embody Diana, but the wigs she wore had a huge effort in bringing this role to life.

Period films or TV shows are no joke for the hair and makeup team [3]. Similar to the costume design [4], both the wigs and makeup have to visually establish the time period the audience is thrust into. Cate Hall, the makeup and hair designer for The Crown seasons three and four, spent months collecting photo research in chronological order to prepare for production. With season 4 picking up in the 1970s, we can expect to see maximalist trends from the '80s make subtle appearances, including Diana's preference for colourful eye makeup [5] and her iconic feathered shag [6] that goes through a low-key transformation of its own.

Hall recently shared some behind-the-scenes secrets in a Netflix press release. Ahead, we've picked out the juiciest parts you need to know before watching season four.

Diana's Iconic Haircut Makes an Appearance

In season four, we really get to see Princess Diana go from a relatively average teenager to an independent young 20-something. Although this time span proves to showcase an emotional evolution for Diana, her hair doesn't significantly change. "Emma's own hair colour is really similar to Diana's natural hair colour, but Diana's haircut was what defined her look, even un-styled it is unmistakably her." Hall said. "Her wigs throughout the season all have precisely the same 'Diana cut' but vary in colour and styling, becoming progressively blonder and more glamorous [and] voluminous."

The No-Makeup Makeup Approach Was Key

Historically speaking, royals have followed bizarre beauty trends (white lead in the Middle Ages was all the rage). However, Mary Greenwell [7], former makeup artist of Princess Diana IRL once told Stylist [8] that this princess was keen on a consistent skin-care routine to keep her complexion looking as fresh and radiant as we remember. With that said, Hall barely used any base makeup on Corrin's skin while filming some of the earlier episodes in the season. In fact, she used no foundation at all on the actress from episode 1 through 5.

Blue Eyeliner Became Her Staple

As we go deeper into the season and hit peak '80s maximalism, Diana's beauty look shifts, albeit subtly. Hall said her team used makeup trends specifically from that decade to age Corrin while also emphasising her emotional narrative. "We knew from research, for example, that Diana would apply her iconic blue eyeliner [9] and mascara when she felt vulnerable and targeted," said Hall. This may come as a shock knowing that the royal family dress code [10] can be quite limiting to more dramatic and colourful beauty looks — this is why you almost never see the Queen and Kate Middleton wearing a wine-red nail polish. Alas, this bolder eye look is one that's still largely associated with Princess Diana, even today.