Pippa Middleton reportedly wants her wedding guests to change before the reception

If there's one thing Pippa Middleton learned from her show-stopping gown at William and Kate's wedding, it's that outfits matter -- which is why she wants everyone to change theirs on her big day.

She will be marrying James Matthews at St. Mark's church on May 20, and she reportedly has all kinds of rules. One is her "no ring, no bring" policy for wedding guests (though she's seemingly made an exception for Meghan Markle).

SEE ALSO: What you should never, ever, ever do at a wedding

Now, in a move labeled by Vogue as "unusual" and "slightly high maintenance," everyone who attends the actual wedding will need to bring a change of clothes: one for the ceremony and one for the reception.

So, has she planned dressing rooms for people? Are there lockers to store their other outfits? Hmm.

Her sister may be the queen one day, but that doesn't seem to be stopping Pippa from being queen for a day!

Scroll through to see how much each part of Pippa's wedding is expected to cost: