Fergie has apparently also been informed that she must avoid three members of the royal family on the day: Prince Philip, Prince Charles and Princess Anne.
Royal commentator Victoria Arbiter wrote on Twitter that she would be missing Eugenie's big day not out of ill will or malice, but because she had "already committed to attending a school event".
'We learnt something yesterday that neither of us had heard before that Catherine and Meghan will wear something they've worn before so as not to upstage the bride?' He said. "Royals don't like to disappoint".More news: Florida, Alabama bracing for 'monstrous' Hurricane Michael
Princess Eugenie and Jack Brooksbank have been dating for seven years and announced their engagement in January. Rather, Camilla will be occupied with a work-related matter that was scheduled before the date of her step-niece's wedding was revealed.
"The family understood, particularly Eugenie, and were fine about it owing to her previous commitment".
There was also speculation that Kate Middleton would not be able to attend the wedding, as her sister Pippa Middleton is expected to give birth to her first child any day now.More news: Meet Spock in ‘Star Trek: Discovery’ Season 2 Trailer!
Although Camilla won't be in attendance, there's sure to be a star-studded guest list to make up for it.
When Queen Elizabeth II's granddaughter Princess Eugenie walks down the aisle Friday in Windsor Castle to marry Jack Brooksbank, a "commoner" with blue-blood friends, the critics will be out.
Find out how to watch the wedding here.More news: John Prine Among 2019 Rock and Roll Hall of Fame Nominees
- Aussies bridle at horse race ad on Sydney Opera House
- The Walking Dead Season 9 Premiere Ratings Lowest Since 2010
- Yankees ace Luis Severino not seeing eye to eye with Pedro Martinez
- Microsoft may be purchasing Fallout: New Vegas developer Obsidian
- Microsoft puts Windows 10 update on hold after file deletion reports
- Pixel 3 and 3 XL pre-orders, pricing, availability, and more
- Bulgaria detains suspect over killing of journalist
- NASCAR Cup Series Driver Power Rankings after 2018 Gander Outdoors 400 (Dover)
- Vaccinations Stressed as Flu Season Begins
- Scientist warning over climate change and global warming - CBBC Newsround