It Won't Be Long by The Beatles is a classic rock song signifying the anticipation and excitement of reuniting with a loved one. The key theme revolves around longing and the joy of a forthcoming reunion. It reflects the universal emotional experience of waiting eagerly for a significant other. Particularly poignant moments in the song include the repetitive use of the phrase 'It won't be long,' underscoring the imminence of the joyous reunion, and the infectious, upbeat melody that embodies the excitement and emotional uplift the narrator feels.