February 27, 2016 - Pascal Le Segretain/Getty Images North America
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19.
Lorde
Who: Lorde
What: Recording artist
Why she's an 'It' girl: Taylor Swift's best friend rose to international stardom with the 2013 release of her song "Royals" making her the youngest solo artist to achieve a US number-one single on the Billboard Hot 100 since 1987. She went on to win two Grammy Awards in 2014 for "Royals" including the highly coveted award for Song of the Year.