Though ZZ Top formed in 1969, Gibbons and Hill did not don the beards until nearly 10 years later, and their decision to do so was by coincidence. After returning from extended vacations, Gibbons and Hill learned that each had let their beards grow long, according to the album liner notes for the band's 2004 release, Rancho Texicano: The Very Best Of ZZ Top.
"[The manager] called a band meeting, and when the three members arrived, they noticed something had changed during their time apart," music journalist Tom Vickers wrote. "They had always had some form of facial hair, with Frank usually sporting a mustache, while Billy and Dusty had scruffy little beards no more than an inch or two long."
Gibbons explained his reaction to seeing Hill's beard. "I walk into the room, and I'm lookin' at a guy I think I know," he said. "My beard has grown to doormat proportions. And I realize that Dusty had done the same thing."