LAS VEGAS, NV - DECEMBER 02:  Singer Lady Gaga poses backstage during the 'Sinatra 100: An All-Star GRAMMY Concert' celebrating the late Frank Sinatra's 100th birthday at the Encore Theater at Wynn Las Vegas on December 2, 2015 in Las Vegas, Nevada. The show will air on CBS on December 6.  (Photo by Kevin Mazur/WireImage)