"Egg Nog Day," which falls on Dec. 24 every year, celebrates the traditional holiday drink after which it is named.
Eggnog is a seasonal holiday drink made of eggs, milk or cream, sugar, and, oftentimes, rum or wine.
Every year, eggnog gets brought out before Thanksgiving and often accompanies the Thanksgiving meal. It then takes a short break until the Christmas season arrives, according to Holiday Insights, a website that offers details on various holiday traditions.
"No one seems to know who created National Egg Nog Day," the website says. "But, egg nog lovers are ecstatic that this day exists."
Regardless of the legitimacy of the holiday, the public is certainly happy to celebrate both Christmas Eve and "Egg Nog Day" together.
Merrymakers have already started sharing festive messages on Twitter.
"Unknowingly celebrated [with] an Egg Nog Latte from @starbucks. … Merry Christmas Eve! December 24 is National Egg Nog Day," tweeted @BuckheadLife on Twitter.