She wanted to keep her other life under wraps until she had scaled back her day job, to avoid becoming a distraction.
She added: “My whole goal was to keep it a secret until I was [ready to] step back from my doctor job, so it wouldn’t be like everyone I work with suddenly knew and it compromised my ability to do my job.
“But I have stepped away from my job. I’m only working like once or twice a month.”
In 2023, she stopped working full time, as she reduced her commitments.
Although some colleagues discovered her secret, they kept quiet about her true identity, with some of her workmates even turning out to be fans without realising the author was at the hospital with them.
McFadden, who became “completely overwhelmed from trying to do both”, is relieved to be “unmasked”, although she wants the book world to keep using her pen name.
She said: “Even though I haven’t told my real name until now, I feel like I have shared the real me all along and everything I’ve told them has been the truth.
“Even though the name will be a surprise, nothing else will. I’ve always been genuine with my readers.”
McFadden’s sequel The Housemaid’s Secret is also being adapted for the big screen, with production getting underway later this year,
Sweeney will be back as Millie Calloway, while Kirsten Dunst is joining the cast.
With the movie coming late in 2027, Erin Westerman, Lionsgate Motion Picture Group president, recently said in a statement: “It is a privilege to bring The Housemaid’s next chapter to the screen with Kirsten Dunst.
“She is an icon. Her career reflects extraordinary range and fearlessness. Opposite the ever-magnetic Sydney Sweeney, she will be an electrifying force in a world where nothing is ever quite as it seems.”