Gabaldon spoke at the Penguin Random House Open House event, in which she explained the decision to pull the pair apart.
Upon taking a question about writing in different character voices, Gabaldon explained: “Some people are very difficult to write.
“To begin with Brianna was very difficult to write – and that’s because she was not a character who came to me.
“She just made herself known. She was a character who I had from necessity because Claire was pregnant at the end of Dragonfly in Amber.”