Lady Gaga attends Billboard's 10th Annual Women In Music at Cipriani 42nd Street on December 11, 2015 in New York City. (Photo by Grant Lamos IV/Getty Images)

Singer Madonna performs during her concert at the AccorHotels Arena in Paris, France, December 9, 2015, on her Rebel Heart Tour. (Photo by Benoit Tessier/Reuters)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

South Korean actress singers Tiffany (R) and Seohyun react in front of an official camera on the red carpet during 2015 Mnet Asian Music Awards (MAMA) in Hong Kong, China December 2, 2015. (Photo by Bobby Yip/Reuters)

The Photographers 2015 runs from 25 November to 23 December at Osborne Samuel and Beetles+Huxley, London. Here: Untitled, 1950, by Bert Hardy. (Photo by Bert Hardy/Beetles+Huxley & Osborne Samuel)

Host Jennifer Lopez performs during the 2015 American Music Awards in Los Angeles, California November 22, 2015. (Photo by Mario Anzuoni/Reuters)

Singer Zendaya arrives at the 2015 American Music Awards in Los Angeles, California November 22, 2015. (Photo by David McNew/Reuters)

Ricky Martin perfoms "La Mordidita" during the Latin Recording Academy Person of the Year gala honoring Brazilian singer Roberto Carlos in Las Vegas, Nevada November 18, 2015. (Photo by Mario Anzuoni/Reuters)