4. Niall Horan

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Yeah, you’re forgiven if you can’t tell any of the One Direction boys apart, but all you need to know is that Horan got a major dental makeover that has greatly enhanced his smile and probably the number of young female fans who scream when he flashes his pearly whites. And when you’re in a boy band, those screams are the difference between banking millions of pounds, or appearing in an episode of “Whatever Happened To?”