Songfacts®:

• Here, Luke Hemmings, Michael Clifford, and Calum Hood trade off vocals about the worthwhile chaos of a relationship.
  
  Caught up in Heaven, but your Heaven ain't the same
  But I've never been a saint, have I?
  Oh, you make me complete
  You make me complete
  You make me a complete mess
  
  The title refers to a favorite tee-shirt of Luke Hemmings he wore during the band's early years touring. It read: "YOU COMPLETE MEss."
• Created during a writing trip in Joshua Tree, the four band members wrote "Complete Mess" with Michael Clifford taking on production duties. The anthemic pop track is the first song entirely written and produced by the Australian quartet. "For this record we realized if you want something done that truly represents how you feel, you've got to do it yourselves," 5 Seconds of Summer explained. "We wanted that expansive sound that we naturally gravitate towards when we play together, so we had to learn how to record that."
  
  The band added the song is authentically them and "exactly the kind of music we want to be making right now."
• Photographer and director Lauren Dunn (Ingrid Andress' "Lady Like," Lauren Jauregui's "More Than That") shot the video. The ethereal, dreamlike visual shows the four band members wandering through a desert.
• 5 Seconds of Summer released "Complete Mess" as the lead single from 5SOS5. The record debuted on top of the UK albums chart, earning the Aussie band their third UK #1 album after Sounds Good Feels Good (from 2015) and CALM (2020).