A silhouette of the three members of ZZ Top appears on the cover of their 15th studio album, La Futura, released Tuesday. But who needs to see their faces as long as their trademark chest-length beards are visible and possibly more identifiable than their music catalog that spans 40-plus years?

Guitarists Billy Gibbons and Dusty Hill have been wearing the signature look since the late '70s, while the group's drummer, whose name is ironically Frank Beard, prefers to maintain a clean shave.

[Related: ZZ Top photo gallery]

Gibbons recently revealed that he and Hill were once offered $1 million to cut off their facial hair, but they declined. In 1984, shaver manufacturer Gillette solicited the Rock 'N Roll Hall Of Fame inductees for an ad campaign but they turned down the lucrative opportunity.

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Gibbons told Bravewords.com that they don't regret their decision and still would not take the deal. "No dice," Gibbons said. "Even adjusted for inflation, this isn't going to fly. The prospect of seeing oneself in the mirror clean-shaven is too close to a Vincent Price film…a prospect not to be contemplated, no matter the compensation."

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."

Their new album, La Futura, was produced by Gibbons and Rick Rubin. Its song "I Gotsta Get Paid" is a remake of Lil' Keke and Fat Pat's "25 Lighters" and was featured in the movie, Battleship.

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