The Duchess of Cornwall is going to miss Princess Eugenie marrying her fiancé Jack Brooksbank.
The royal wedding is due to take place at St George's Chapel, Windsor this Friday 12 October but while all other senior royals will be there to witness the younger daughter of Prince Andrew and Sarah, Duchess of York marry, the wife of Prince Charles, will not be in attendance.
But Camilla's surprise absence is reportedly not down to a snub or any bad blood between the royal pair but more a case of clashing diaries.
According to The Sun on Sunday, the Duchess of Cornwall has a long-standing engagement at a school in Scotland to which she committed eight months ago.
Although the Duke and Duchess of York tried to persuade her otherwise, Camilla was adamant that she would not break her promise to the schoolchildren that she would attend their harvest festival.
Speaking to The Sun, a source said: "When this date was proposed, she said that regrettably, she couldn't come.
"The family understood, particularly Eugenie, and were fine about it owing to her previous commitment. Camilla didn't want to let anyone down."
While some were quick to judge Camilla on social media for her absence, royal correspondent for CNN, Victoria Arbiter defended the duchess on Twitter.
"I know it seems odd that Camilla's missing Eugenie's wedding but it doesn't indicate any malice or ill-feeling. Royals don't like to disappoint. Given she'd already committed to attending a school event it's duty first," Victoria, whose father previously worked as The Queen's press secretary, explained.
Camilla may be missing out on royal wedding festivities but come Friday, the rest of the world's eyes will be firmly on the historic market town of Windsor in Berkshire when the younger daughter of Prince Andrew and Sarah, Duchess of York, is walked down the aisle by her father at the very same chapel in Windsor Castle where Prince Harry married Meghan Markle back in May this year.
WATCH: Get to know Princess Eugenie's fiancee, Jack Brooksbank:
Channel 7 have confirmed they will be the only Australian broadcaster with access to ITV's exclusive live coverage of the ceremony from inside St. George's Chapel which means we'll all be able to watch the day as it unfolds from the comfort of our lounge!
Invited guests will be arriving at Eugenie's wedding from 8:30am London time, with the service and carriage ride expected to unfold in the hours following.
New details released by Buckingham Palace reveal some important additions to Eugenie and Jack's nuptials, including a description of the wedding cake that has royal fans salivating.
The pair has chosen a London cake designer, Sophie Cabot, to create the work of art for their big day.
She'll be creating a red velvet chocolate cake, described as a "traditional cake, with a modern feel".
"It will incorporate the rich colours of autumn in its design and will be covered with detailed sugar work including ivy."
The cake creator came to the attention of the royals when she became involved in the Duke of York's Pitch@Palace program, for which she supplied bespoke biscuits.
The statement from Buckingham Palace said Eugenie and Jack were "delighted" that Cabot was involved in the celebration of their nuptials.
Wonder if they'll save a slice for Camilla?