Harry and Meghan are due to tie the knot on Saturday 19 May in front of over 2000 guests.
Fergie wasn't invited to William and Kate's big day but did end up being a part of it in some way thanks to Prince Andrew.
Instead they will hop in a auto for the half a mile journey from Frogmore to Windsor Castle.
As for Markle not inviting her estranged half-siblings, Fitzwilliams says even in royal weddings there's no obligation to invite someone you're not close with.
Among the 2,640-strong guest list for the wedding party in West London are 1,200 "members of the public" from all walks of life, drawn from the four corners of the United Kingdom.
Between 9:30 a.m. and 11:00 a.m. local time, guests will begin to arrive by coach to the Round Tower, which is at the center of Windsor Castle grounds.
So if Harry and Meghan keep up this tradition, we may see Princess Charlotte take up the role as well as Mulroney's young daughter Ivy or Harry's two young cousins, six-year-old Isla Phillips and seven-year-old Savannah Phillips.
"Members of the royal family do curtsy to the queen", said royal historian Hugo Vickers, an adviser for the 2011 Oscar-winning film "The King's Speech".
Prince Harry's best man: Prince William. "This will allow Their Royal Highnesses to acknowledge all of the people gathered in the Castle precincts, including the 200 charity representatives gathered in the Horseshoe Cloister at the bottom of the steps".
"(She) is delighted to have her parents by her side on this important and happy occasion".
Palace officials are determined that the style and designer of Markle's wedding gown will be kept secret until the moment she gets out of the vehicle to walk into the chapel.
While the Daily Mail describes Markle's gown as a "hand-stitched, heavily beaded design", there's no official word yet on what her wedding dress will look like - but that hasn't prevented the world from speculating. Don't miss the scene where the actors playing Markle and Prince Harry pet a giraffe.
The royal couple will be married on May 19.
Mr Welby said: "I'm always nervous at weddings because it is such an important day for the couple - whoever they are".
A 25-minute carriage ride will then begin.
However, considering the royal wedding is still two weeks away, it's hard to know for sure how the forecast may turn out.
The last thing we can expect to officially see is the lovebirds leaving Windsor Castle to make their way to their reception at Frogmore House.