Ace’s “How Long,” a No. 3 hit in 1975 for the British rock band, was the first single to introduce music audiences to the voice of Paul Carrack, who went on to become a vocalist for other influential groups like Squeeze and Mike & The Mechanics. And thanks to a buzzy new TV campaign from Amazon’s Prime and Echo Show tablet, Carrack’s first hit is finding a whole new audience.

The slinky, blue-eyed-soul jam soundtracks a spot dedicated to the streaming-era phenomenon of “binge cheating,” or watching the next episode of a show behind your paramour’s back. The song’s signature bass line and catchy, spurned-lover chorus “How long / has this been going on?” quickly resonated with music fans. In the three days following the commercial’s first airings on March 2, digital sales for the track soared 2,059% to 4,000 downloads, while streams jumped to 831,000 in the week ending March 5, according to Nielsen Music.

“Often in the creative process, you find that its best to write from what you know,” says Simon Morris, Amazon’s vice president global creative, who helped conceive the spot and select the use of “How Long.” “This script stood out, and everyone involved identified with the situation. The song is a personal favorite and was the obvious choice to build the narrative for the commercial. We are glad that it’s proving popular and delighted for the artist Paul Carrack, who wrote this great song.”

The Amazon commercial also marks the first commercial synch secured by BMG, which owns the Ace catalog via its 2014 acquisition of Union Square Music. “In terms of conveying a narrative or story in the short amount of time that you have for commercials, it’s the perfect song — assuming that the creative is about infidelity or cheating or something,” says Charlie Davis, senior director of creative synch – commercials at BMG. “[‘How Long’ is] so cinematic, and I think what just makes that song so great is the bass line is instantly catchy. And then when the vocals come in straight to the hook, it gets right to the crux of the song immediately.”

“How Long”’s unlikely success 45 years after its initial release is the latest chapter in the unique history for a song with both unexpected origins and many owners. For starters, there’s the relationship that kickstarted its narrative. Though the song’s lyrics seemingly allude to a romantic infidelity, Carrack explains that “How Long” was actually inspired by his suspicions (ultimately proven true) that Ace bassist Tex Comer had been secretly conspiring to join another group.

“Ace were a struggling bar band who got together in 1973 to play the pubs around London, really for fun. We were very close, bonded by our two major passions of music and soccer,” Carrack says. “We were friends with a band called Sutherland Brothers and Quiver who were doing rather better than us, as in they had a contract with Island Records and had toured the U.S. supporting artists like Elton John.”

Sutherland Brothers and Quiver’s bassist, Bruce Thomas (who later became a member of Elvis Costello & The Attractions), had apparently missed a few shows, so Comer filled in for him at those gigs before talks expanded. “Although we were pleased for Tex at the time,” Carrack continues, “it soon became apparent that SB&Q were trying to tempt Tex to join them on a permanent basis, which would have been devastating for us at the time. Fortunately for us, Tex resisted the temptation of a regular salary and stuck with us.”

Since its success as a ‘70s AM radio staple, “How Long” has found several other pathways to the airwaves via hit covers by everyone from disco group Lipps Inc. to Rod Stewart.  “I was absolutely over the moon when I had my first ever cover by none other than the great Bobby Womack,” says Carrack of the late soul singer’s 1976 cover. “I believe that Ronnie Wood was instrumental in that coming about. Also Rod’s version later was also a huge feather in my cap…I’ve been playing the song for 45 years both with my own band, with various other bands and even recently as part of the Eric Clapton Band, and I never tire of it.”

Unfortunately, as a result of signing “pretty awful” master and publishing deals with then-label Anchor Records in the ‘70s, Carrack and his Ace bandmates haven’t seen much financial gain from the recent synch boom. “There’s very little rights to me, I was just the idiot that wrote and sang it,” says Carrack, who has re-recorded both “How Long” and some of his best-known Squeeze hits over the years to reclaim some of the performance royalties (as Taylor Swift may be doing with her Big Machine catalog). “Somebody pointed out to me that [‘How Long’] was being used in an ad, so I said, ‘Great, I may see something from the sync rights,’ which could be nice. But I mean, there’s five guys in the band. I don’t think anybody’s ordering a Ferrari just yet.”

Still, despite having to cut his headline U.K. solo tour short a couple dates due to the ongoing COVID-19 crisis, Carrack’s been able to carve out a comfortable living from his independent catalog as a solo artist for the past 20 years, which generates upwards of 1 million streams a month on services like Spotify.

“I’m pretty happy, apart from the bloody virus situation,” he says. “My label’s been good, we’ve built up the touring thing in the U.K. – we sell out a nice 1,500 on average rooms and the fans love it. I just go out there and have a good ol’ sing and a good play and go home.”

Songs for Screens is a Variety column sponsored by Anzie Blue, a wellness company and café based in Nashville. It is written by Andrew Hampp, founder of music marketing consultancy 1803 LLC and former correspondent for Billboard. Each week, the column highlights noteworthy use of music in advertising and marketing campaigns, as well as film and TV. Follow Andrew on Twitter at @ahampp.