In June 1994, Princess Diana stepped out in an off-the-shoulder black evening gown following Charles's public revelations that he had been unfaithful to her. Diana's dress was quickly deemed her “revenge dress,” and in the 30 years since, it has been a near-constant point of sartorial reference in pop culture. (See: Taylor Swift, for example.)

Amelia's black column gown featured a deep v-neck and some sparkle on the thin straps, while Eliza's featured more of a sleeve with a sculptural detail on the bodice. Each wore a diamond necklace, earrings, bracelets and rings. No matter how you look at it, though, both Spencers took a page out of Princess Diana's style book.

Lady Amelia Spencer and Lady Eliza Spencer, the twin daughters of Princess Diana's younger brother Charles Spencer, 9th Earl Spencer, wowed as they hit the red carpet