Accessorizing, Markle added a hunter green crossbody bag courtesy of Scottish label Strathbury, which highlighted the similar shade of green in her jacket.
Una Mallon, a mother of four, 47, from Belfast, said she thought Meghan would become "our new Diana".
The choice of wearing tartan can also be seen as a subtle tribute to Scotland.
They met members of the public during a walkabout in the Scottish capital on the eve of Valentine's Day. The "Suits" actress will not have a bridal registry, instead, she and Prince Harry "want to encourage friends, family, and well-wishers to donate anonymously to a charity gift fund".
But what has she been doing? She said: 'I bought these last night, I don't mind if Meghan or Harry takes them.
Harry told the organisers: "I long for the moment that the values and principles you have shown in setting this up are no longer exceptional". Everyone was really excited for Harry and Meghan's arrival.
Afterwards they went to Social Bite, a cafe which makes over 100,000 meals for the homeless in Scotland each year, and employs those who used to be homeless themselves.
Harry and Meghan will speak with staff, tour the kitchen and learn more about the enterprise.
Harry, 33, and Markle, 36, were officially welcomed to the city by the Royal Marines Scotland Band at the castle, where they observed the firing of the one o'clock gun, a tradition that dates back to 1861.
The firm also plans to open a "village" for homeless people later this year, which would give people without accommodation a home so they can try to find some security.
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