Sarah Ferguson was once the pariah of the royal family and was banned from attending private royal engagements. Yet despite this strained relationship, the Duchess of York still remained close to one former in-law.

Ferguson made the surprising revelation while appearing on Jessica Rowe’s podcast, The Jess Rowe Big Talk Show, to promote her latest book A Woman of Intrigue.

The 65 year old former royal was discussing family life when she opened up to Rowe and revealed her close bond with Queen Elizabeth, who she felt closer to than her own mother.

“The thing about the Queen was that she was more my mother than my own mother,” Ferguson said.

“The Queen was an iconic, legendary, stalwart, steadfast, invisible hand of love behind your back.”

Although Ferguson enjoyed a warm relationship with the Queen, she never fully relaxed around her ate mother-in-law.

“You certainly were in awe, and therefore you kept your wits about you,” she said.

“She’s one of the greatest leaders of our time.

“I mean, she was the grandmother of the nation. She was the steadfastness of an extraordinary pillar of strength for the Commonwealth, for the nation, for Australia, for the world,” she said before adding she was “greatly missed.”

These days, Ferguson enjoys a loving relationship with her royal in-laws and has become a self-described a badass grandmother” to Princess Beatrice and Edoardo Mapelli Mozzi’s daughter Sienna, 2, Moapelli Mozzi’s young son Christopher Woolf, 7, from a previous relationship, and Princess Eugenie and Jack Brooksbank’s sons August, 3, and Ernest, 9 months.

“I am a badass grandmother with a sense of purpose, a badass grandmother, a sexy, sappy, badass grandmother,” she said.

She also bravely faced two life-changing health battles, firstly triumphing over breast cancer and then was recently given the all after being diagnosed with a melanoma.

With those difficult days now behind her, Ferguson has opened up about the emotional transformation these experiences have sparked.

“My melanoma scars, the scars of my cancer, it took me being literally carved up to cut away the addictions of self-doubt and self-judgment that I have lived with since the age of 11,” she told the Daily Telegraph.

While her cancer journey was no doubt daunting, Ferguson revealed that coming out on the other side shifted her perspective entirely.

“When I got cancer I put my life back in the middle and food back in its rightful place, not intentionally,” she said.

“It just happened because I realised that I was eating instead of living.”