This is the opening track of Currents, Tame Impala's third album and the follow-up to Lonerism. Frontman Kevin Parker told NME this song introduces a theme running through Currents of personal advancement. "'Lonerism is about always shutting out the outside world," he explained, "but chapter one of the next story, you realise that at some point there's so much force around you that to fight it just takes more energy to shut it out. There's a big undercurrent theme of transition, a transition of the self as a person. It's about giving in to forces that you can't control, even though your whole life seems to be wrong."
"'Let It Happen' is like chapter one – it's track one, but it's also the first step," Parker continued. "It's about someone finding themselves in this world of chaos – they realize it, but they've always been blocking it out, they've always been stopping the outside world from coming in, like blocking their ears."