Many people find it hard to wait until Christmas morning to open beautifully-wrapped presents, and Princess Diana was self-admittedly one of them. The Princess of Wales struggled to keep herself from opening presents before time, a "dreadful" habit she passed on to her eldest son as well.

In a letter she wrote to a friend in 1985, Princess Diana confessed tearing into her gifts before opening time even as an adult. In the letter, the royal also mentioned that her son, Prince William, who was a three-year-old at that time, also shares this habit with her, reports People magazine.

"A parcel of any shape or form has never been safe with me. And I fear that William has also picked up this dreadful habit from his mother, as I find wrapping paper undone in the most extraordinary places," the late princess had written.

In another letter she wrote to a friend in 1990, the British royal talked about how much her sons Prince William and Prince Harry, who were aged eight and six at that time respectively, look forward to the Christmas holiday and the gifts they will receive.

"The boys are thrilled at the prospect of Christmas on the horizon and have searched high and low for any parcels that might be coming their way!" she had written.

Diana was also fond of the royal tradition of exchanging inexpensive gag gifts on Christmas Eve, though she couldn't do it on her first royal Christmas as a newlywed in 1981. The princess wasn't aware of the tradition and presented her sister-in-law, Princess Anne, with an expensive cashmere sweater in exchange for a toilet paper cover.

However, she quickly became a pro at giving gag gifts and once pranked her youngest son Harry by putting fake dog poo in his stocking.

The late princess' two sons, whom she shared with ex-husband Prince Charles, are celebrating Christmas separately this year. While Prince William is spending the holiday with his wife Kate Middleton, and children Prince George, Princess Charlotte, and Prince Louis at their country home Anmer Hall in Norfolk, Harry is marking his first Christmas as a financially-independent royal in a newly-bought home in Montecito, California, with wife Meghan Markle and son Archie.

Rarely seen photos of Princess Diana
Diana holds Prince William’s hand as they leave the Royal Yacht Britannia after a cruise around Scotland’s Western Isles in August 1985 Tim Graham/Getty Images