Jordan Strauss / Invision/AP 1 / 15
Jordan Strauss / Invision/AP 1 / 15

Wonderwall Editors

Ever since she completed treatment for bipolar disorder and a host of other issues, Demi Lovato has been somewhat of an open book when it comes to her personal life. And in an appearance on New York radio station WBLI's "Dana & Jeffrey in the Morning" on Monday, she let a new bomb drop about herself.

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"I just got to know … I have an older sister that I've never known my whole life," said the young singer. "She's in her 30s. She's my half-sister. I talked to her for the very first time in my life around when I turned 20 [in August 2012]."

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"I asked her, 'Why haven't you ever contacted me?'" Lovato continued, relaying the details of their initial conversation. "She just said, 'Well, because I never wanted you to think that I wanted anything from you. So I've just kind of been waiting to see if you wanted a relationship. I thought that was so incredible.' So I actually have three sisters!"

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