Selena Gomez says she has lupus, underwent chemotherapy

Pop star Selena Gomez reveals in a new interview that she has been diagnosed with lupus, an inflammatory disease that can cause fatigue, joint pain, skin rashes and hair loss.

In the issue of Billboard magazine out Thursday, Gomez says she went through chemotherapy treatment during some of time she spent out of the spotlight this year.

"That's what my break was really about. I could've had a stroke. ... I locked myself away until I was confident and comfortable again."

The "I Want You To Know" singer, 23, also discussed the impact of the body-shaming she experienced this summer, when online commenters and tabloids criticized paparazzi photos of her in a bikini.

"That was the first time I'd experienced body shaming like that," Gomez says. "I believed some of the words they were saying."

She appears to have risen above the criticism, though, as the singer appears nude on the cover of her new album, "Revival," out Friday.