MultiFemale Singers in the video : Fifth Harmony Little Mix Miley Cyrus Demi Lovato Selena Gomez Lady Gaga Britney Spears Taylor Swift Madonna Christina Aguilera Jennifer Lopez Rihanna Shakira Marina And The Diamonds Alyson Stoner Ashley Tisdale Ariana Grande Jessie J Ciara Aly And AJ Janet Jackson Nicole Scherzinger Beyoncé Zendaya Gwen Stefani