The Chainsmokers feat. Halsey - 'Closer'
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The Best Selling Songs Of 2016 Have Been Revealed!
3. The Chainsmokers feat. Halsey - 'Closer'
Alex & Drew were THE act to watch in 2016! Not only was 'Closer' on EVERYONE'S playlist, it sold an impressive 2,124,000 copies. The duo have come a long way since their semi-novelty '#Selfie' became a viral success in 2014 - and this isn't their only appearance on this countdown. (Pic: PA)