One's a pop icon and the other's - well - a pop icon, and yesterday (21 May) they came together in Chicago in the most dramatic way as Hertfordshire's own Charli XCX covered The Backstreet Boys' 'I Want It That Way'.
It happened in Chicago's Borderline Music store with Charli taking the Boys' angst anthem and sprinkling it with '86-era Madonna dreaminess. Did she improve it? Did she murder it? Have a listen and tell us what you think.