On Thursday, Prince William and the Duchess of Cambridge will celebrate their tenth wedding anniversary.
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The royal couple married in Westminster Abbey on 29 April 2011, and the historic venue marked the event on its Twitter account – they just made one tiny error.
"The wedding of TRH The Duke and Duchess of Cambridge in the Abbey ten years ago today was a joyful occasion, celebrated in the UK, the Commonwealth and around the world," they wrote in a commemorative tweet, alongside the hashtag "#RoyalWeddingMemories."
Relive Prince William and Kate Middleton's royal wedding
Although the royal couple's marriage was a joyous occasion, by posting their tribute on Wednesday, the Abbey was a day early!
Westminster Abbey's account finished its Twitter thread with a snap of a dated order of service for the marriage, which further highlighted the unfortunate error.
Royal watchers were quick to point out the mistake, as one wrote: "Tomorrow is the 29th, not today."
A second said: "The anniversary is tomorrow?" while a third added: "Except it is ten years tomorrow not today. It was 29th April and is still 28th April today! Or am I going crazy?"
The couple were married in Westminster Abbey
The royal couple usually celebrate their anniversary privately, and although they may do so again this year, they have the option of enjoying a special meal at a restaurant as coroanvirus restrictions are eased.
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Last year, Kate was actually working on the special day, joining a roundtable discussion via video link with charities that support new mothers and pregnant women.
In the case of their fourth anniversary, the Duchess was overdue with the couple's second child, Princess Charlotte.
For their first anniversary in 2012, William and Kate spent the weekend in Suffolk, where they attended the wedding of the Duchess' school friend, Hannah Gillingham, the day before.
Kate cooked her husband fish en papillote – fish wrapped in parchment paper – as a nod to the traditional first wedding anniversary gift of paper.
The royal couple have three children together
Westminster Abbey is an emotional venue for Prince William, as not only did he celebrate his wedding to Kate Middleton there, but it was the funeral venue for his mother, Princess Diana.
Elton John, a close friend of Princess Diana's once commented on this during an interview, saying: "I can't imagine at that young age having to walk in the public, following your mother’s coffin…
"And the next time we're in the Abbey it's to see him walking up the aisle with a beautiful woman, the love of his life. I think it's the most joyous result and I'm sure Diana would be very, very happy about it."
The wedding featured other nods to the Duke of Cambridge's mother, as the service sang the hymn Guide me, O though great Redeemer, which was sung at Princess Diana's funeral and Kate walked down the aisle to The Introit, a piece of music from Diana's wedding to Prince Charles.
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