This stripped down, confessional acoustic song was penned by frontman John O'Callaghan with a friend while walking through a cemetery in England. He recalled to Billboard magazine: "Right before that trip... I had turned 23 and was talking to - I use that term loosely - 'talking to' a girl that lived in Los Angeles. For the first time I think I felt what it's like to be on the opposite side of a letdown or the built up emotion of a relationship... also just being confused of things, what your role is in a relationship. So I came up with the metaphor of LA or Los Angeles being this girl."
The bedrock of David Guetta's Nicki Minaj-featuring single "Hey Mama" is a sample of "Rosie," a 1940s prison recording from folk archivist Alan Lomax that songwriter Esther Dean first showed the French DJ on YouTube.