Demi Lovato has discovered she has a secret half-sister.

The 'Skyscraper' singer has revealed she recently reconnected with her long lost older sibling, who she only found out about this year.

The 20-year-old star told Long Island, New York web radio station WBLI on Monday (04.03.13): "I think my fans would be excited to learn that I just got to know I have an older sister that I've never known my whole life.

"I actually have a third sister that I didn't even know about until this year. She's in her thirties. She's my half-sister, but I talked to her for the first time in my life when I turned 20.

"I asked her 'Why haven't you ever contacted me?' and she said 'I never wanted you to think that I ever 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!"

The 'X Factor' USA judge, who has two other sisters Dallas and Madison - also recently rekindled her relationship with Wilmer Valderrama for the third time.

The 'Give Your Heart A Break' singer - who has dated the former 'That 70s Show' star on and off since 2010 - spent Valentine's Day (14.02.13) with the 33-year-old actor at Takami Sushi & Robata Restaurant in downtown Los Angeles, where they cuddled throughout their meal.

Demi - who checked into rehab for three months in October 2010 where she successfully received treatment for her eating disorder and problem with self-harming - recently revealed that she is finally in a place where she wants to be in a relationship.