Middleton wore the original design in 2012 to an official dinner hosted by Malaysia's Head of State.
The duchess pulled it out of her closet again for the 2020 BAFTAs but had it changed to include a layer of fabric on the sleeves so that they would no longer be sheer.
"With this particular dress, it appears she adapted the sleeves to flatter her figure, adding a lining and shoulder pads to create a more structured look," Anthony McGrath, leading fashion journalist and senior lecturer at the Fashion Retail Academy, previously told Insider. "This means the dress frames her face better and enhances her posture."