LOOK: Fashion photographer Mario Testino posts beautiful photo of Princess Diana

Christmas is a time of giving.

For acclaimed photographer Mario Testino, the act of giving brings back fond memories of the late Princess Diana, who died 23 years ago in a tragic car crash in Paris, France.

The Peruvian lensman posted a stunning photograph of Diana on Instagram and mused about his encounter with the Princess of Wales for a magazine photoshoot in March 1997.

“I was commissioned to photograph Princess Diana for Vanity Fair, to promote the auction of her gowns,” reminisced Mario.

“All the proceeds were destined to support the charities close to her heart.

“Meeting her and getting to know her generosity first hand taught me how giving can change everyone's lives for the better.”

Diana at the time was stepping out from the shadows of her ex-husband Prince Charles.

The two officially divorced on August 28, 1996, although the couple was already living separately since 1992.

The Vanity Fair photoshoot was designed as a coming-out party of sorts for Diana as a celebrity and humanitarian, someone who wanted to use her royal status as leverage to help more people.

“We were there to shoot some pictures to show the Princess in a new light,” wrote British fashion editor, Meredith Etherington-Smith, in a retrospective piece for The Guardian in 2015.

It was Meredith who introduced Mario to Diana. She also facilitated the auction of the princess' clothes for charity in which the photoshoot aimed to highlight.

“She wouldn't be heavily made-up, jeweled and tiara'd in the stiff ballgowns of her royal life. She'd be in simple, modern clothes with no jewelry. Her make-up and hair would be kept to a natural minimum to suit the new non-ceremonial life she had started to lead - and her extraordinary natural beauty.

Meredith recalled the moment Diana stepped inside the studio housed on the second floor of an old school building in Battersea, south of London.

“I remember she was wearing a very sharp little black and white houndstooth suit which had been the star of John Galliano's recent show for Dior, and even though she had hardly any makeup on she looked wonderful - slightly pink and gasping from all the stairs she had negotiated.”

Diana's photographs from that day would be a defining moment in her post-royal career and legacy.

The portraits showed Diana, still looking regal, but in a relaxed and casual mood.

“No one had ever seen the princess look natural, fun, and modern in the way that Mario revealed that day,” wrote Meredith, who died in January of this year from a heart attack.

But more importantly, the charity auction was a success, helped largely by the Vanity Fair piece and the accompanying photographs published in July 1997.

“I got a letter from her shortly afterward saying that the shoot in the old Battersea schoolroom had been one of the happiest days of her life. It showed, I think, in the photographs,” Meredith wrote in closing.

For Mario, the photographs he took that day would become an iconic representation of Diana as a person years after her untimely passing.

“[Diana] opened a door for me because I then started photographing the royal families of Europe extensively ... this brings out my love for tradition, for a way of showing family and the longevity of people,” Mario confided.

Mario would become an ambassador for Save the Children. He later helped fund the reconstruction of the El Salvador Clinic in the Pueblo Nuevo District, Chincha in Peru, following an earthquake in 2007. The hospital was built to extend medical assistance to children afflicted with tuberculosis.

He was able to raise enough money after selling a print from his portraits of Princess Diana in an auction.

Princess Diana's photographs, as Mario would realize, are gifts that keep on giving.