Songfacts®:

• "Must Be" is J Hus' first official single following his release from jail in April 2019. The rapper had been sentenced to eight months in prison for carrying a knife in public. The song gave Hus his first UK Top 5 hit.
• Here, Hus raps in his customarily laid-back flow about how he doesn't trust his surroundings.
  
  If it walk like a opp, talk like a opp
  Smell like a opp then it must be a
  If it look like a opp, chill with a opp
  Hang with a opp then it must be
  
  Hus' rivals or 'opps' seem to him to be skulking everywhere. These people all walk, talk and act in a particular way; even if they don't claim to be his enemy, they are guilty by association.
• The Afrobeats-influenced beat comes from Hus' frequent collaborator JAE5, who oversaw the production on the London rapper's debut album Common Sense.