She shares the romantic detail in a new two-part documentary about the royal family, Queen of the World, which starts on Tuesday.
"To have such a monumental moment in England, nonetheless of all the places, I felt like we were literally watching history", she told The Project. "Fifty-three countries as well, my goodness, it will keep us busy".
She adds: "It's fabric from the dress that I wore on our first date".
In a clip from the upcoming HBO documentary Queen of the World, Meghan reveals she had a secret tribute to her first date with her now-husband hidden within her attractive 16-foot wedding veil.
She married Prince Harry at St George's Chapel in Windsor Castle in May. Tucked somewhere inside her stunning wedding veil was a secret "something blue".
"It was important for me, especially now being part of the Royal Family, to have all 53 of the Commonwealth Countries incorporated and I knew that it would be a fun surprise as well, for my now husband, who didn't know", Meghan says in the newly-released clip posted on the Royal Family's official Twitter account.More news: Brett Kavanaugh: Second woman accuses US Supreme Court nominee of sexual misconduct
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According to her, each flower represents one of the 53 nations of the Commonwealth.
"Queen of the World" premieres Monday, Oct. 1 on HBO at 8 p.m.
She added: "It's lovely ― diversity, inclusivity, coming together in grief or joy ― there is just so much love".
Meghan has been a fan of Aquazzura for a long time, wearing a white satin pair of the Italian brand's heels with her Stella McCartney dress during her evening wedding reception at Frogmore House on May 19.
Markle isn't alone in adhering to this strong British wedding tradition - Sarah Burton of Alexander McQueen confirmed she slipped a blue ribbon into the side seam of Kate Middleton's gown back in 2011.
In another more recent "twinning" moment, Princess Eugenie - Beatrice's younger sister - wore the same Aquazzura heels as Meghan during a night out with fiance Jack Brooksbank earlier this year.