Lady GaGa is opening up about a really difficult time. In 2017, it appeared the 39-year-old pop star was on top of the world amid all her success after performing at the Super Bowl, headlining Coachella, and working on the award-winning film A Star Is Born with Bradley Cooper. But in reality? GaGa was struggling. In a cover story with Rolling Stone, published on Thursday, the Bad Romance singer got candid about the hard chapter in her life - revealing she "did A Star Is Born on lithium." Whoa.