Songfacts®:

• This is one of three songs that Edinburgh-based multiracial hip-hop trio Young Fathers contributed to the T2 Trainspotting soundtrack. The movie is based on Irvine Welsh's book Porno, which describes the characters of Trainspotting ten years after the events of the earlier book.
• The song features vocals from the Leith Congregational Choir. The Edinburgh choral group had preciously jumped onto Young Fathers' remix of Paul Weller's "Saturn's Pattern."
• T2 Trainspotting director Danny Boyle described this as one of the songs that forms the movie's "heartbeat".
  
  He said: "Trainspotting, the original book is like a modern Ulysses. It's unsurpassed I think, and reading it is still like the 'rush of ocean to the heart'. You're always looking for the heartbeat of a film. For Trainspotting it was Underworld's 'Born Slippy'. For T2 It's Young Fathers. Their songs are my heartbeat for the film. And 'Only God Knows' is that rush again. The ocean. The heart."
• Speaking to NME, Young Fathers said the song came about organically. "We did it when we were out in LA," Kayus Bankole explained. "It just felt like it fit the whole vibe of the film, so we gave it to Danny [Boyle], and he put it just at the end sequence bit of the film. That's it – it stands alone with the film."
  
  Bankole added regarding the lyrical content: "It was just vibes in the moment – it was the first thing that came to us when we were recording the song. It felt right and we just went for it. There was no pre-meditated agenda, it was just 'this is how I'm feeling at the moment – let's f---ing go for it.'"