As Princess Diana's younger brother, Charles Spencer, trades blows with Buckingham Palace over his new memoir, there's at least one person firmly in his corner. On publication day for "Swan Song: Diana, My Sister," his wife, Cat Spencer, took to Instagram with a message of support, alongside a photo of the 9th Earl at work in his study at Althorp, the Spencer family's ancestral home.
© Tim Graham Photo Library via Get"Happy publication day! I am incredibly proud of you. I've been endlessly impressed by your resilience and determination this past year, from the moment you decided to go ahead with this project: all those mornings you got up at 4am to write; some days the memories you unearthed were glorious, others they were utterly heartbreaking," reads the message.
"I'm so pleased people can finally read Swan Song for themselves and get a glimpse into the sister you wrote this book for. I feel very lucky to be by your side."
Cat's words land at a charged moment. Spencer spent years writing the book, which he conceived as a way to preserve Diana's memory from a point of view no one else can claim. Spencer grew up alongside her at Althorp and was with her through her childhood and her death.
Buckingham Palace's reaction
The book's arrival in stores on Tuesday was preceded by days of headlines over its allegations regarding King Charles III, Diana's ex-husband.
The publication inspired a rare response from Buckingham Palace. "While we do not comment on books as a matter of principle, His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgment and colour memory in ways others do not recognise, even many years after such a loss," said a spokesperson for the King.
Spencer has stood by his account. "Is he furious or is he embarrassed?" he said of the King's response, as reported by NPR.
Through it all, Cat has been at his side. She's also an expert on the subject. Before her marriage put her in royal headlines, Cat Jarman, as she was known before her marriage to Spencer, had built a career of her own. Born in Norway, she earned a PhD in archaeology from the University of Bristol and specialized in the Viking Age. Her 2021 bestseller, "River Kings," follows the Vikings' trade routes and expansion from Scandinavia all the way to the Silk Roads.
© Princess Diana ArchiveThat book is what first brought them together. Spencer, himself a historian and author, was asked to review a copy of it. The two developed a professional connection that became a romance.
On May 15, 2026, the couple married in a private ceremony in Sedona, Arizona, with the red spires of Cathedral Rock as their backdrop. They never announced an engagement. Days after the wedding, they shared a joint statement and wedding photos.
"We both feel so incredibly lucky to have progressed from being colleagues to friendship, to deep love and connection," they told PEOPLE.
It's the fourth marriage for Spencer, 62, and the second for Cat.
The wedding came roughly two years after Spencer's split from his third wife, Karen Spencer, which led to a contentious divorce. Spencer is a father of seven. With his first wife, Victoria Lockwood, he shares Lady Kitty, twins Lady Eliza and Lady Amelia, and Louis, Viscount Althorp. He has two children, Edmund and Lady Lara, from his second marriage to Caroline Freud, and a daughter, Lady Charlotte Diana, with Karen.
© Anwar Hussein
