Why Meghan Markle was snubbed from Pippa Middleton's wedding

The Duchess of Cambridge's younger sister, Pippa Middleton, married husband James Matthews on May 20, 2017, six years after the Duke and Duchess of Cambridge tied the knot.

Duchess Catherine decided against being a bridesmaid or maid of honour at her sister's ceremony, which took place at St. Mark's Church in Englefield, so not to "upstage her sister", royal correspondent Judy Wade told PEOPLE at the time.

Kate attended her sister's wedding, while her children Prince George and Princess Charlotte took on the important roles of pageboy and bridesmaid.

However, Meghan Markle was absent from the ceremony, and only attended in the afternoon so not to "overshadow" the event.

During this time Prince Harry had been dating the former Suits actor for five months, and it was already known they were in a relationship together.

According to Finding Freedom authors, Omid Scobie and Carolyn Durand, because royal fans were desperate to see the new couple together it was the sole reason why Meghan was not invited to the full day of celebrations.

The authors have also alleged Meghan - who has son Archie and daughter Lilibet with Harry - had bought her outfit for the wedding.

But after Pippa Middleton's figure, and pert posterior, was a huge headline around Kate's wedding, they thought the same focus would be on Meghan and her appearance, instead of the bride and groom.

They wrote: "Harry and Meghan agreed that she couldn't possibly turn up at the church, only 50 metres away from a specially arranged media pen, after such a crass cover story.

"If they worried their arrival might create a media circus despite taking every precaution, now they had no doubt that it would.

"Meghan's church outfit and Philip Treacy hat would have to be worn another time."

Harry attended the wedding ceremony solo, and was joined by Meghan later in the evening, although it has been claimed he had to drop his then girlfriend to a wedding guest's Airbnb before making his way to the church.

Meghan waited for Harry to return so they could have lunch together, prior to attending evening celebrations at the Middleton's family home, although they were separated once again due to the seating arrangement.

The book, which has seen segments published on the Daily Express, read: "Sitting together in the custom glass marquee that has been erected on the 18-acre property should have been a fun night for the couple, but, per Pippa's request, no couples sat together."

But the rule was not out of spite, and instead to encourage guests to mingle with one another.