For decades, Baby, It’s Cold Outside has been treated like a Christmas classic. But the song was never actually written for Christmas at all.

Songwriter Frank Loesser wrote the duet in 1944 as a playful performance piece for himself and his wife, Lynn Garland. The couple would sing it together at glamorous New York parties, usually near the end of the evening. It became their signature routine and an elegant hint that guests should probably head home.

The song’s winter setting eventually caused it to become associated with the holidays, even though the lyrics never mention Christmas, Santa, or New Year’s. When MGM later used it in the 1949 film Neptune's Daughter, the song exploded in popularity and went on to win an Academy Award for Best Original Song.

Some lyrics have sparked debate in modern years, especially the line “What’s in this drink?” But historians note that in the 1940s, the phrase was often used jokingly, as a socially acceptable excuse for flirtation at a time when women faced heavy social pressure to appear reserved.

So one of the world’s most recognizable “Christmas songs” actually began as a private cocktail-party duet between a husband and wife who accidentally created a holiday standard.