The wedding guests are expected to gather at the St. George's Hall of the Windsor Castle where they will be joined by the newlyweds after their carriage procession.
As the couple were greeted by Frank Ross, Edinburgh's Lord Lieutenant and Lord Provost, who represented the city, Prince Harry took a moment to give Cruachan IV a pat on the nose.
And the in-demand fashionista is rumoured to be helping select Meghan's all-important wedding dress.
Also sold out are the $395 Vernica Beard bootleg Adley Pants she wore underneath her coat, which she paired with a simple, black long-sleeved top. The lavish green coat is believed to have cost £1,995 (A$3,524, U$2,770).
The future royal also told the waiting crowds that her hen do was already "sorted" and "will be fun".
Meghan teamed it with wide-legged Veronica Beard trousers and a Wolford turtleneck bodysuit.More news: Yoel Romero Likely to Get Next Shot at UFC Champ Robert Whittaker
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According to the Daily Mail, rather than carrying a neat clutch like Kate or a handbag in the style of the Queen she was the first royal to step out with a trendy cross body bag, opting again for Scottish brand Strathberry.
The pony later used his Twitter account (1067 followers) to blame Harry for the nip: "The prince was teasing me".
They met with a Shetland pony, who was also wearing a tartan coat. The pair were keen to chat with staff and talk about their experiences and how they changed their lives around.
Harry and Meghan then visited Social Bite, a café and social business that tackles homelessness - a cause close to Harry's heart.
The last public part of the couple's day saw them visit the Great Gallery of the Palace of Holyroodhouse, where they were serenaded with an accoustic version of Ed Sheeran's ideal by a group of 50 young people. It's all about celebrating and recognising the achievements of Scotland's younger community members and about providing them with new and exciting opportunities.
The trip to Scotland marks the fourth public appearance Meghan, 36, and Harry, 33, have made together. They have previously appeared in Nottingham, London and Cardiff in Wales.