However, when it came to the reception, as E! reported, Markle was welcome to be Prince Harry's plus one!
The 33-year-old is marrying a wealthy financier at the oh-so-English 12th-century church of St. Mark's in the village of Englefield, west of London - with a guest list of young A-list royals and reality TV stars looking on. She also joined Harry in Jamaica in March for the wedding of his best friend, Tom "Skipp" Inskip.
For her wedding to Prince William in 2011, the Duchess of Cambridge wore the royal family's Cartier Halo Scroll tiara complete with 739 brilliant-cut diamonds and 149 baguette sparklers.
The sister of the Duchess of Cambridge looked every inch the royal bride.
Middleton, who arrived at the church with her father, Michael Middleton, was a handsome bride in a custom silk cotton lace gown by Giles Deacon.More news: Rep. Al Green Officially Calls on Congress to Impeach President Trump
George and his younger sister Princess Charlotte, 2, had roles in the ceremony as pageboy and bridesmaid respectively.
Harry did not bring his girlfriend, American actress Meghan Markle, to the crowded church ceremony.
While Pippa's sister Kate Middleton was spotted leaving Kensington with husband Prince William earlier in the morning, the duchess was not pictured outside the church prior to the ceremony - presumedly meeting her sister inside so as not to take attention away from the bride. His younger brother is Spencer Matthews of "made of Chelsea" fame.
Prince George of Cambridge, page boy, and Princess Charlotte of Cambridge, bridesmaid, for Pippa Middleton and James Matthews' wedding.
The Duchess of Cambridge has already admitted she is a little anxious about how her children will behave. She may attend the private reception.More news: Jurgen Klopp says talks have begun in exciting revelation
Escorting Markle to such a high-profile event would be seen as confirmation that the relationship is increasingly serious.
Despite Miss Markle's lack of an appearance at the church, it is believed she attended the evening reception, although no pictures have emerged of the guests enjoying the celebrations yet.
She looked terrific in a form-fitting Alexander McQueen dress at Kate's wedding, nearly but not quite upstaging the bride, but is likely to wear something more modest at her own. Middleton is expected to wear a traditional, embroidered gown, most likely with the spectacular beadwork and detailing that mark high-end British fashion. Markle is set to attend Pippa Middleton's wedding on May 20, 2017 with boyfriend Prince Harry.
Hatmaker to the stars Stephen Jones - also known for his veils - may also be involved.More news: Mourinho to give Dearnley, Gomes, Harrop, Mitchell and Willock their United debuts
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