And the blame lies solely on the shoulders of her new husband, Prince Charles.

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Families hold on to some pretty strange Christmas traditions, and the British Royal Family is no different. Unfortunately, newlywed Princess Diana wasn't given a crash course in them before spending her first holiday at Sandringham House…

It turns out that the Windsors have a hilarious tradition—every Christmas Eve (at 6 p.m., sharp) the family exchanges gag gifts in the red drawing room of the Queen's country estate. According to InStyle, Prince Philip "supervises the proceedings" and tells the rest of the clan when it's time to open their "cheap and cheerful" gifts.

Past gifts of note include the "Grow Your Own Girlfriend" kit Kate Middleton gave then-single Prince Harry and the leather toilet seat Princess Anne gifted her brother Prince Charles.

But back in 1981, Prince Charles said nothing of this gag gift tradition to his new wife, leaving her to commit a painful holiday faux pas.

WATCH: Nobody Knows What Became of Princess Diana's Secret Backup Wedding Dress

Looking to play it safe for her first Christmas with her famous in-laws, Diana reportedly gifted Princess Anne a nice cashmere sweater. And in return, Diana received a toilet paper cover from her new sister-in-law.

Yikes.

But the people's princess didn't let it keep her down. The next Christmas, she reportedly recovered by bestowing a leopard-print bath mat upon Duchess Fergie.

Now that, ladies and gentlemen, is what we call grace.

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