When Prince Charles's engagement to Lady Diana Spencer was announced, on the surface she appeared to be the perfect traditional bride for a future King. She belonged to an aristocratic family with close ties to the palace, and had been around royal protocols and mannerisms all her life.

However, the Princess of Wales turned out to be drastically different, often forgoing royal traditions to do things from her heart, like hugging members of the public at her royal engagements. Rather than fitting into the royal ways, Diana later made the unprecedented decision to leave her marriage with the Prince of Wales and start a life of a single mother.

A clip from an old interview with the Princess from before her wedding indicates that she gave a glimpse of her strength and her spirit even back then. The archive clip, which is going to be featured in CNN's upcoming documentary series "Diana", was from her and her fiancé Charles's interview with ITV to discuss the nuptials.

Prince Charles had already left the public confused after he made the "whatever in love means" comment at their engagement interview when asked if he is in love with Diana. This interview was also equally awkward, as interviewer Andrew Gardner's general question about their hopes for newlywed life was met with stilted silence, reports People.

Gardner then went into the specifics and asked Diana if she was looking forward to making a home at her future husband's Highgrove estate in his Duchy Cornwall. The then 20-year-old replied, "Oh yes, very much so, looking forward to being a good wife," with what might be a hint of mischief in her eyes.

Her fiancé sputtered "gracious" in response, along with an awkward smile. Diana then added, "I have to say that, you're sitting there!"

It was revealed much later that Diana often stayed at Kensington Palace in London as her husband spent time with his longtime love and current wife Camilla-Parker Bowles, who lived in Cornwall with her husband Andrew Parker Bowles and their two children. It is said that Diana had discovered around the time of the wedding that Charles and Camilla's affair had not ended, as she believed it had, which is why she appeared sceptical about settling in Highgrove in the interview.

Angela Rippon, who conducted the interview alongside Gardner four decades ago, says in the upcoming CNN documentary that Diana's comment reflected her tough nature. "There was something more to Diana, something that was not the marshmallow or the Play-Doh that was going to be molded into what they [the royals] wanted. Running through all of it was a backbone, a knowledge of her own self," she explained.

According to a press release, the six-part documentary about Diana "re-examines the life of an icon through the lens of modernity: reframing her story to discover the real woman behind the 'People's Princess.'" The series aims to show how she was "truly a blueprint for the modern woman."

Princess Diana
12 November 1980: Nineteen year-old Lady Diana Spencer, Prince Charles's girlfriend, leaves her flat at Coleherne Court in Earl's Court, London Hulton Archive/Getty Images