Prince Harry and Meghan Markle's relationship is developing at a rapid pace. There was no problem for Meghan to attend a Wedding last March when Harry's best friend got married in Jamaica. Meghan has been invited to be Harry's date at Pippa Middleton and James Matthews' wedding on May 20, but the invitation comes with a big stipulation.

Meghan's invitation

Meghan Markle reportedly received an evening-only invitation. That means she won't be attending the actual wedding ceremony in the church. Instead, she has to wait until the church part of the wedding is over before she joins the others at the reception.

It is not unusual for people to be invited to attend a wedding but not the reception because the couple wants to cut down on the price of the meals. That is not the case with this wedding.

Reason for the evening-only invitation

Some believe Pippa wants only family members, married couples, and engaged couples to attend her wedding. According to People magazine, the real reason is that Pippa doesn't want to take the chance of the "Suits" actress upstaging her and causing unnecessary chaos. It is enough to think her own sister, Catherine, the Duchess of Cambridge, will make the headlines because of her wedding. However, she can't keep Kate away, especially since her own children will be in the wedding.

Prince George will be the page boy, and Princess Charlotte will be Pippa's bridesmaid.

Some people think it is rude for Pippa to tell Meghan to stay away from her wedding in the church but feel free to come to the evening-only celebration. After all, Meghan is taking a week off from work and has to travel for hours from Toronto to England.

Yet, she is invited to be in attendance for only half of the wedding celebration.

Etiquette expert, Zarife Hardy, who directs The Australian School of Etiquette, says it is impolite to invite a guest to only part of a wedding. The bride and groom should never make a guest feel second best or as an afterthought. It is rude for someone to be invited to the wedding but not the reception, or invited to the reception but not the wedding.

It was pointed out that Pippa is a party planner and has written a book on the subject. Therefore, she should know a better way to handle this delicate situation.

While this might seem like it is a personal snub towards Meghan, the actress is not alone. Pippa has not invited reality television star Vogue Williams to her wedding. Williams is dating the groom's younger brother, Spencer Matthews. Williams is shrugging the non-invite off by saying she has something better to do than to attend Pippa and James' wedding, but she wishes them the best.