For her engagement interview, the princess-to-be wore a blue off-the-rack skirt suit from Harrods that perfectly matched her sapphire and diamond ring.
But it was her wedding dress designed by David and Elizabeth Emanuel that was a real eighties extravaganza.
The taffeta and lace dress with a record-breaking six metre train was hand-embroidered, with more than 10,000 mother-of-pearl sequins and pearls and reportedly cost around £90,000 (AU$164,000 by today's standards).
But even her more casual outfits reflected the decade's trends with bold colours and striking silhouettes.
As she settled more into royal life and became a much-loved public figure, fans noticed that Diana's fashion mirrored her increasing confidence and maturity.
Gone were the "safe" styles of her late teens and early twenties, and this was certainly reflected in her chic evening gowns that she donned for official evening engagements.
Her blue chiffon dress at the 1987 Cannes Film Festival was designed by one of her favourite designers, Catherine Walker and she sometimes re-invented looks - on a 1985 formal night out, Diana repurposed her emerald choker as a headband.
Even Emma Corrin, who plays young Diana in season four of hit Netflix drama The Crown has weighed in on the late royal's style and how you can trace her character arc purely through the costumes.
"She starts out in these very mousy, sloaney, really not great outfits. But then we leave her with this insane backless dress, and that’s the trajectory from girl to woman, with a lot of bumps along the way," the actress explained to Variety.
"I love that for the majority of the series her fashion is s***. I think Diana’s fashion always blinds you a bit so you don’t really recognise who was behind there and where she started. Our series takes her back to a pretty clueless little girl."
Following her divorce and humanitarian ventures in the 1990s, Diana's style changed once more. But that's a story for another day...
