In the picture, Diana, who often donned outfits by Valentino, wears a white blazer with puff sleeves and a turquoise trim with a matching skirt and clutch.
She appears to be speaking to the two fashion moguls while Mr Garavani smiling at her.
The second picture shared by Mr Giammetti shows a relaxed-looking Princess Diana on a yacht with Kyril of Saxe-Coburg – the second son of Simeon Saxe-Coburg-Gotha, Prime Minister of Bulgaria from 2001 to 2005 – and the Italian designer.
Her eyes are covered by wide sunglasses, but the late Princess of Wales can be seen smiling to the camera while holding a drink.
Mr Giammetti shared these pictures, alongside with two other snaps of the Princess of Wales wearing Valentino outfits, after the release of the fourth season of The Crown.
This season, taking place between 1979 and 1990, heavily focused on the first nine years of marriage between Prince Charles and Diana.
Mr Giammetti wrote on Instagram: “TV The Crown has once again reminded us of the struggle of Princess Diana!”
Introducing the two never-before-seen snaps, he added: “And here two moments of friendship with her.”
The latest season of The Crown appears to have rekindled the outrage surrounding the affair during the late 1980s and 1990s of Prince Charles and Camilla, Duchess of Cornwall.
Many fans of Princess Diana or the Netflix’s show have taken to Twitter to attack Prince Charles and Camilla for their old affair.
Following the rise in online criticism and attacks, Clarence House, the press office for the Duchess and the Prince and social media account, have limited the possibility to reply to new posts and videos on Twitter only to accounts mentioned or followed by it.
When asked for the reason behind this move, Clarence House did not comment.
Royal commentators have warned some of the viewers of the show may have been led into thinking the Prince of Wales and Camilla had been involved in an affair throughout his marriage with Diana as portrayed on screen.
In reality, many experts have said Prince Charles and Camilla had little contact between 1981 and 1986.
Royal author Sally Bedell Smith told Vanity Fair: “While the earlier seasons were period pieces, this is recent history, so it seems more cruel in its false depictions.”
She continued: “He did not enter into the marriage cynically, thinking he could keep a mistress on the side.
“He was telling the truth when he said to Jonathan Dimbleby on camera in 1994 that he had remained faithful to his wedding vows until his marriage to Diana became ‘irretrievably broken down’ in 1986, when he resumed his intimate relationship with Camilla.
“It’s fair to say that between 1981 and 1986, Charles and Camilla were in telephone contact when he was in distress and needed a sympathetic ear, but their physical relationship was in abeyance for five years.”
Source: EXPRESS CO UK