The 1950s were the heyday of the Rat Pack, the famous group of Hollywood entertainers whose members included the likes of Frank Sinatra, Dean Martin, Sammy Davis Jr., Peter Lawford, and Joey Bishop, among countless others.

The Rat Pack went on to become one of the era’s most bankable groups of stars and established a legendary reputation in Hollywood thanks to movies like Ocean’s 11 and Robin and the 7 Hoods. But long before then, the group had to earn its name—and few people know that it was one of Hollywood’s most famous actresses who gave them it.

According to legend, early in their collaborations together the group would often hang out at Humphrey Bogart’s home in the Holmby Hills area of Westwood, Los Angeles.

One night, after a particularly rowdy night on the town (or, according to one version of the tale, a particular rowdy trip to Las Vegas!) the group stumbled back to Bogart’s house in the early hours of the morning to be met by a less than impressed Lauren Bacall, Bogart’s wife of almost a decade.

“You look like a goddamn rat pack!” Bacall exclaimed—and from then on, the group was the “Holmby Hills Rat Pack.” The reference to Westwood was eventually dropped, and Hollywood’s legendary “Rat Pack” was born.