Teen television star turned singer Selena Gomez has revealed that she has lupus and secretly underwent chemotherapy to treat the disease.

The now 23-year-old pop star canceled a tour of Asia and Australia in December 2013, saying she needed to spend time alone and check into a rehabilitation center in the desert state of Arizona.

The move sparked a tabloid frenzy amid rumors she was battling addiction or heartbroken over her breakup with Justin Bieber.

But in an interview published Thursday, Gomez said she suffered lupus, a chronic disease in which the body's immune system fights healthy tissue.

"I was diagnosed with lupus, and I've been through chemotherapy. That's what my break was really about," she told music magazine Billboard.

"I wanted so badly to say, 'You guys have no idea. I'm in chemotherapy. You're assholes,'" she said of the tabloid press.

"But I was angry I even felt the need to say that. It's awful walking into a restaurant and having the whole room look at you, knowing what they're saying.

"I locked myself away until I was confident and comfortable again," she said.

Gomez said that she has been helped out in part by her friendship with pop superstar Taylor Swift, who "makes me feel empowered."

Lupus is estimated to strike some five million people around the world, disproportionately women of childbearing age, according to the Lupus Foundation of America.

While Gomez did not go into greater detail about her lupus, the disease is commonly treated with Methotrexate, a chemotherapy drug used at much lower doses to fight inflammation. One potential side effect is hair loss.

Since the episode, Gomez has returned to an active schedule. Her second solo album, "Revival," comes out on Friday.

The celebrity website Popdust had initially reported on Gomez's lupus diagnosis in 2013, at which time the singer's representatives declined comment.