Princess Diana's kind-heartedness has often been attested to by those who were closest to her. As the single employees who worked for the Royal Household in the late-1980s would surely agree...

It became a traditional in-joke for Diana to send each loveless member of her staff a Valentine's Day Card. Each novelty card bore her autograph.

This particular example dates to 1989 and was gifted to "George", a footman and valet. After signing the card, Diana had it gifted to him in a pink envelope.

Following George's recent death (his surname has not been publicly revealed), the late footman's family are now auctioning the card. It carries a £8,000 (approximately $12,600) presale estimate.

Diana's good-natured Valentine's Day card to her footman, George

According to reports, George himself was something of a collector of Royal memorabilia during his time working for the Windsors. And he wasn't the only collector to a kept a memento of Diana's kindness...

An auction in Lincoln, UK, last month included the sale of an autographed Princess Diana letter written to a nine-year-old boy named Roger.

The signed letter was penned just two months prior to Di's Royal wedding to Prince Charles. It sold to an internet bidder for just £425.

This was a fantastic bargain, especially if you consider that Diana's autograph value has risen by 616% on average in the last 11 years.

Diana remains a blue chip in today's collectibles markets - and this will no doubt be confirmed at the upcoming sale or her Valentine's Day card for George.