ZZ Top finally delivered their fourth album Fandango! to record stores on April 18, 1975 to truly unprecedented excitement. It had been nearly two years since they'd last dropped some brand-new music upon their growing legion of fans. Still, thanks to the breakthrough success of their third long player, Tres Hombres, that little band from Texas were now bigger than ever before.

So big, that the trio of Billy Gibbons (vocals, guitar), Dusty Hill (bass, vocals) and Frank Beard (drums) had easily sold out the University of Texas football stadium in Austin to the tune of 80,000 tickets. This special occasion was amusingly dubbed the First Annual Barndance and BBQ, but the droves of attendees wound up doing so much damage to the playing field, just ahead of the Longhorns’ first game of the season, that concerts were banned for 20 years at Memorial Stadium.

But not before providing some amazing photographic evidence for the inner sleeve – in part to help explain their long absence from recording, and in part to inform fans that ZZ's long-awaited return was in fact a a half-live, half-studio proposition.

The good news was that this unorthodox arrangement in no way compromised the band's ability to give their fans exactly what they hungered for: Southern-smoked blues and boogie, as tender as a Texas brisket.

First came the live side, led by the driving “Thunderbird,” paying twin praise to the popular automobile and the low-budget wine, and accompanied by enthusiastic shouts of “Get high, everybody, get high!” Next came Hill's growling rendition of Leiber & Stoller’s “Jailhouse Rock,” and then a nearly 10-minute “Backdoor Medley,” featuring Gibbons’ naughty “Backdoor Love Affair” split in half with Willie Dixon’s “Mellow Down Easy” sandwiched in between (complete with drum solo), before concluding with John Lee Hooker’s “Long Distance Boogie.”

Listen to ZZ Top's 'Tush'

For its part, side two of Fandango! introduced no less than six exhilarating new studio cuts, as strong as anything contained on the celebrated Tres Hombres.

First there was the badass groove of “Nasty Dogs and Funky Kings,” then the exquisitely soulful “Blue Jean Blues, the raunchy “Balinese” and utterly politically incorrect “Mexican Blackbird,” as well as the heartfelt tribute to border-crossing Mexican radio stations in “Heard it on the X.”

The best was saved for last: “Tush,” which became ZZ Top’s first Top 20 single, pulled Fandango! right along with it into the U.S. Top 10, and has since yielded more cover versions than one can count. Way back in 1975, though, what all of these new heights of success meant for Gibbons, Hill and Beard was an even more aggressive touring workload.

Starting in Huntington, W.V., on Fandango!'s April 18 release date, they played the first of more than 60 concerts before their final date on Nov. 30, in Green Bay. And to give you an idea of ZZ Top’s popularity, check out some of the bands chosen to open their shows during this almost year-long trek: Kiss, Blue Oyster Cult, Status Quo, R.E.O. Speedwagon, and Aerosmith

In other words, ZZ Top were clearly among America's top-grossing acts during that time span, and their ambitions would only grow taller on the following year's both infamous and legendary World Texas tour.

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