Meghan Markle on the secret item from her first date with Prince Harry hidden in her wedding veil.

Prince Harry’s wife Meghan has revealed she only saw the finished version of her five-metre long, show-stopping elaborate silk veil on the morning of the nuptials.

Speaking in Queen Of The World, a two-part British ITV show on the Queen’s role as head of the Commonwealth, Meghan revealed other personal details about her May wedding at Windsor Castle.

Following the bride’s tradition of having something old, new, borrowed and blue on her wedding day, Meghan had a piece of material sewn into her Givenchy gown as her “something blue”.

“It’s fabric from the dress that I wore on our first date.”

And she says she only saw her completed veil – embroidered with flowers from each of the 53 Commonwealth nations – on the day she married, having trusted designer Clare Waight Keller after seeing initial sketches.

“Then after that point, I just said I trust her implicitly with what she did, and I didn’t see it really until the morning of, so this is my first time seeing the veil like this.”

Meghan makes her comments when she is reunited with her bridal outfit at Buckingham Palace as it is prepared for a new exhibition, and says: "It's nice to see it again. It's beautiful."

Meghan said the veil's design was intended as a patriotic surprise for Harry.

"It was important for me, especially now being a 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, and he was really over the moon to find out that I would make this choice for our day together.

For a raw, unedited, and slightly inappropriate Royal Wedding debrief...

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"And I think the other members of the family had a similar reaction, and just appreciation for the fact that we understand how important this is for us and the role that we play, and the work that we're going to continue to do within the Commonwealth countries."

Meghan and Harry will begin their first major Commonwealth tour next month arriving in Sydney on October 16 for the Invictus Games and travelling around Australia, New Zealand, Tonga and Fiji.

"You know, it's such an exciting time for us, especially with Harry's role as Youth Ambassador for the Commonwealth and the travel that we intend to do, to do work specifically in all those different territories," Meghan said.

"Which is why it was so important to have some sort of example of that present with us on the (wedding) day, 53 countries as well, my goodness, It'll keep us busy."