According to the Mayo Clinic, lupus is "a chronic inflammatory disease that occurs when your body's immune system attacks your own tissues and organs." Organs affected by lupus include the kidneys, heart and lungs.
The "Come & Get It" singer also responded to rumors her time off from the spotlight was for drug or alcohol addiction.
“I wanted so badly to say, ‘You guys have no idea. I’m in chemotherapy. You’re a------.' I locked myself away until I was confident and comfortable again," she added. "I'm so f------ nice to everybody, and everyone is so vile to me. I’ve been working since I was 7. I’ve been a UNICEF ambassador since I was 17. It’s so disappointing that I’ve become a tabloid story."
But with an upcoming album title "Revival," she said the "hate motivated me."
Then there were the body shamers she recently faced on Social Media, firing back, "I was in a bikini and got publicly ripped for being overweight. That was the first time I’d experienced body shaming like that. I believed some of the words they were saying."
She said she's over that now and not afraid to show off her figure, even for her upcoming album.