This week, UMG is releasing the official soundtrack album for the NBC series This Is Us, network TV’s big breakout hit of the 2016 Fall season, ahead of the premiere of its second season. The album is a mix of contemporary indie rock and familiar FM gold representing the show’s two timelines, one in the present day and one in the late ’70s and early ’80s. But there’s one slight outlier: lead actress Mandy Moore’s new studio recording of “Willin’.” The trucker ballad about booze and pills, written by the ’70s cult band Little Feat, was performed by Moore’s character Rebecca last October in the fifth episode of the drama.

This month a version of “Willin'” also appeared on late rock legend Gregg Allman’s final album, Southern Blood. And last year, a few weeks before Moore sang it on This Is Us, “Willin'” played a significant role in two episodes of Cameron Crowe’s short-lived Showtime series Roadies, where it was covered by Jackson Browne. Frank Zappa sideman Lowell George wrote “Willin'” in the late ’60s, and while it became the signature song of his band Little Feat, it has never appeared on a Billboard singles chart, instead taking its own strange little path to becoming a pop-culture staple.

“Willin'” was inspired by people Lowell George met while working at a gas station in Southern California before his music career took off. And the delightfully alliterative list of towns he rattles off in the chorus — “I’ve been from Tuscon to Tucumcari, Tehachapi to Tonopah” — took shape as he hitchhiked through the Southwest. George’s first big break came when he joined Frank Zappa’s Mothers Of Invention at the peak of the band’s fame, appearing on 1970’s Weasels Ripped My Flesh. But by the time the album was released, George’s six-month tenure in the band was over.

The legend around “Willin'” is that it directly led Frank Zappa to fire George, although there are two fairly different narratives about why: Either the song was so good that Zappa insisted it was time for George to lead his own band, or the song’s chorus refrain celebrating “weed, whites and wine” offended Zappa, who famously turned his nose up at drugs and alcohol.

“I was smart enough not to submit it. But he did hear it once, and a few days later I was offered to start my own band, which was a nice way of firing me, I think,” George explained in an Austrialian radio interview in 1978. In Ben Fong-Torres’s 2013 book Willin’: The Story Of Little Feat, Little Feat co-founder Bill Payne suggests that both narratives are true. “I think Frank was both impressed and put off by the song because of the drug reference. He was somewhat conservative on certain levels.”

Before forming the band, George signed with a publishing company that shopped around “Willin'” and “Truck Stop Girl,” a similarly themed early Little Feat song. The Byrds recorded both for their 1970 album Untitled, although only “Truck Stop Girl” made the cut for the album’s release (“Willin'” was later featured on a reissue of Untitled, and Byrds member Gene Parsons featured the song on his 1973 solo debut).

The first attempt at recording “Willin’,” on Little Feat’s 1971 self-titled debut, was a little off. The simple vocal and guitar arrangement has a faster tempo that rushes through the tongue-twisting lyric instead of lingering. And since George, a revered slide guitarist, badly burned his hand on the engine of a model airplane during sessions, Ry Cooder stepped in to play the track’s lead guitar. Little Feat revisited “Willin'” a year later for a full-band version on their second album, Sailin’ Shoes, which became the definitive arrangement upon which all future versions were based. It wasn’t the single, thanks to the risqué chorus, but it didn’t much matter; Little Feat never had a Hot 100 hit.

Over the course of the ’70s, “Willin'” became a country rock staple, recorded by Johnny Darrell, Seatrain, and Commander Cody And His Lost Planet Airmen. But it’s best known for its appearance on Linda Ronstadt’s 1974 breakthrough album Heart Like A Wheel. Ronstadt and George had a brief tryst, which she’d recall with self-deprecating humor while introducing the song in her concerts. In this 1977 clip, she talks about falling for the guitarist in Atlanta. “He was amazing … Unfortunately, he was married, which he didn’t tell me until about a week later. His old lady turned up on my doorstep at about 10 in the morning.”

Ronstadt sings “Willin'” beautifully, and does nothing to alter or gender-flip the song’s lyric, told from the POV of a male trucker daydreaming about his “Dallas Alice.” When This Is Us’ Rebecca sings the song, she’s definitely an aspiring Ronstadt. And Mandy Moore may seem like an odd interpreter for the song, but she’s been branching out from her teen pop beginnings since the 2003 album Coverage, which featured songs written by XTC and Todd Rundgren.

Lowell George’s own drug use may not have been too far off from the trucker he described in “Willin’,” and he died at just 34 years old in 1979. But Little Feat later reformed in the late ’80s and have recorded and toured steadily since then, celebrating and building upon the body of work George amassed beyond “Willin'” that included the Feat’s first seven studio albums. Their music has trickled down through generations in countless ways, including the drum break from 1973’s “Fool Yourself” that was used in hits by A Tribe Called Quest and the Fugees.

In the 21st century, the status of “Willin'” as a roots-rock standard has been bolstered by dozens of recordings by artists including Tom Petty, Steve Earle, the Black Crowes, and Brooks & Dunn, who sang it with Little Feat on their 2008 album Join The Band. The placements in This Is Us and to a lesser extent Roadies have placed Little Feat into a pop-culture firmament that it was at one point safe to assume the band would never penetrate. But you will still probably never hear “weed, whites, and wine” on the radio.