The song turned them into global superstars - but Thin Lizzy almost didn't release The Boys Are Back in Town.
Former guitarist Scott Gorham has revealed that band members didn't rate the single and it was only after an intervention by their record label that it was included on their 1976 album Jailbreak.
"Back then, you picked 10 songs [for an LP] and went with those because of the time restrictions of vinyl. We recorded 15 songs, and the 10 we picked, that wasn't one of them," he said.
"But then the management heard it and said, 'No, there's something really good about this song'," he added.
Scott Gorham of Thin Lizzy
The rest was history as the anthemic song topped the charts in Ireland and was a hit in both the UK and the US.
In an interview with Classic Rock magazine, Gorham said the band, including Dublin-born front-man Phil Lynott, were not instant fans of their most successful song.
"We were playing in some club in the US when our manager came in and said, 'Well, looks like we've got a hit.' We were like, 'Which song?' Seriously, we didn't have any idea at all which song it was that had taken off for us."
Gorham said the song's success and the fact it was nearly not released is a lesson in "how thin the line can be that separates success from failure".
"I always say: 'Don't listen to me - I'm the one who thought The Boys Are Back in Town shouldn't have been a single!'"