After exchanging vows with Prince Harry last month at Windsor Castle, the former Suits star (36) solidified her place on the top of best dressed lists - and made the case for a second wedding dress - in a bespoke McCartney gown, which was largely declared as the preferred look of her two dresses on her wedding day.
Earlier, she walked up the aisle in a Claire Weight Keller for Givenchy gown which divided critics, a nod to the more businesslike direction her wardrobe would be taking when she became a royal, but it was the second number that showcased the effervescent personality synonymous with her style.
McCartney said she had to tread a "delicate line" of dressing appropriately for the occasion while also ensuring the bride looked "a million dollars". She told the BBC: "I feel it’s such a private experience. And as a designer and as a woman who’s been married - I had to do my dress - it’s such a big deal.
"It was very much her dress, and I felt very proud that she came to me for that part of the wedding. She got to reflect her in it."
It was Markle, now the Duchess of Sussex, who approached the British fashion legend about working together on the dress and presented a number of ideas.
"When you come to a wedding, you don’t just go ‘here, this is what you’re wearing’. That person has to feel like a million dollars, they need to feel like they own it," she explained.
"The role she’s taken on, it’s very austere, it’s very sort of serious, and I think there’s a great weight that she has acquired through that and she takes it very seriously.
"I think it was the last moment that she could reflect sort of the other side to her: the joy and the human within her.
"I was aware that we had to get the right kind of positioning, the right pace, the right voice. There was a delicate line."
Since her wedding, Meghan has made two public appearances and during both, she has already adopted a more duchess-like approach to dress, including flesh coloured tights and a string of fascinators.
McCartney also designed looks for royal wedding guests Oprah Winfrey and Amal Clooney.