Sarah Ferguson Shares Why She Feels 'Liberated' After Queen Elizabeth's Death (Exclusive)

The late monarch died on Sept. 8.

Sarah Ferguson is opening up about life following Queen Elizabeth II's death. In a conversation with ET's Rachel Smith, the 63-year-old Duchess of York reveals why she feels "liberated" six months after the monarch's death.

"I am growing much more in my own voice now. I think also the queen dying has sort of liberated me a bit. My sense of purpose has always been, for 62 years, 63 years, to be very loyal and to uphold Her Majesty's values," Ferguson explains. "She was more a mother to me than my own mother, really, and therefore now she's not there anymore, I feel as though maybe I can be free to be Sarah. I feel as though I'm liberated from my own mental shackles."

Ferguson, who calls the late queen "an iconic legend," made sure to soak up all of Her Majesty's wisdom as they walked her beloved corgis together, pups that Ferguson has now taken into her care.

"I would be very ignorant if I did not study every time I was with Her Majesty, just ask questions... [I would ask] 'How do you manage with a new prime minister? How do you manage to filter chaos as well as you do?'" Ferguson recalls. "... I also thought how lucky I was 'cause every single moment I was with Her Majesty I felt such an honor... I have been the luckiest girl, I really have."

Since the queen's death, Ferguson, who's felt "quite invisible" for most of her life, has now developed the "confidence" to be herself.

"I don't think I've shown anybody the real Sarah that you're seeing today. I'm very authentic today... There's nothing holding me back now. I sort of feel free to be myself," she says, before sharing what changed her mindset.

"The switch was I think realizing I had a career, and I wasn't just the duchess, and that I'm a strong, redhead, and it's OK to be strong, it's OK to be very colorful and feisty," Ferguson says. "... I'm very lucky to be here mentally. I think I've been through many mental issues. [I've had] quite the journey... I've become more savvy."

The career Ferguson mentioned is as a writer, as she's gearing up to release her new novel, A Most Intriguing Lady.

"As I was researching, I found wonderful Lady Mary, who has a very silent voice in the grave, because her brothers were written about, but she wasn't," Ferguson explains. "We need to empower women, and empower women in literature, empower women in life, and so I took her out of the grave and said, 'Right, Lady Mary, you're going on an adventure.'"

Ferguson is also delighting in watching her two daughters shine as "stellar mothers." Princess Beatrice is mom to Sienna, 1, while Princess Eugenie has a 2-year-old son, August, and is expecting her second child.

"I've got back to playing Barbies," Ferguson, whose grandchildren call her "GiGi," tells ET. "... I'm learning how to play trains now... We do afternoon tea at 5:00 every single day."

Elsewhere in the family, the royals are gearing up for King Charles III's May 6 coronation.

"I don't think the invitations have gone out yet, but I'm very happy to watch it on television," Ferguson says. "I think it's such a huge honor to see him be crowned with his lovely queen next to him... He's been so long waiting to be king. It's going to be a very moving day."

Ferguson's historical romance novel, A Most Intriguing Lady, is due out March 7.