“Follow your heart but do you dare," Fergie said in a video announcing the project. "I’m going to take you back with the wonderful Mills & Bon HarperCollins to 1870, to the Lady Margaret," she continued while strolling through a garden.
"Lady Margaret she loves to ride side-saddle. She’s strong, she’s rebellious, she’s courageous."
In a caption accompanying the video, Fergie revealed that the novel, title Her Heart for a Compass, has been co-written by historical romance writer Marguerite Kaye and will be published in August this year.
The Duchess then went on to dish about the plot.
"Set in the nineteenth century, this is a coming-of-age story about being brave and rebellious, and daring to follow your heart against the odds," the 61-year-old wrote.
"The story itself is based on one of my ancestors and I’ve spent the last couple of years doing my own research into my family history with the help of the royal archives. As a result the book is rich in detail of the Victorian era and draws on my own life journey and experiences too – so it is a story very close to my own heart."
The love story is already receiving hype from Fergie's fans.
User @friederikekrum commented, "How fabulous Sarah. 'Brave, rebellious and daring' is what women all need to be!", while @about_the_york_family wrote "Congratulations dear Duchess! As a great lover of Victorian Age I can't say how thrilled I am. Really looking forward to reading it".
While this is the first time Fergie has delved into the world of romance in this way, the Duchess is certainly no stranger to the world of writing.
Back in August last year, Fergie released three books - though they were for a slightly different audience.
“I am so excited about the launch of my 3 new children’s books tomorrow, Genie Gems, Arthur Fantastic and The Enchanted Oak Tree,” Fergie wrote on Instagram last February.
Indeed, the Duchess has already written over 25 books in her time. It looks like she's adding another to the mix!