Demi Lovato on learning about her half-sister, 'That was so incredible!'

Demi Lovato reveals that she has an older half-sister that she never knew until last year.

The singer said that her older sister is in her 30s, E! News reported.

"She's my half sister and I talked to her for the very first time in my life around when I turned 20."

Lovato then said, "I asked her, 'Why haven't you ever contacted me?'" the pop star recalled, "and she just said, 'Well, because I never wanted you to think I wanted anything from you. So I've just kind of been waiting to see if you wanted a relationship,' and I just thought that was so incredible."

The singer just released a single, entitled "Heart Attack," on February 25, and it garnered a lot of compliments from her fans.

The official video lyrics uploaded on YouTube's VEVO, earned more than 500,000 views, whereas the audio of the song received 3.7 million views to date, Billboard reported.

Music critics suggest that she could sell 200,000 first-week downloads, and make a big entrance into the Billboard 100 by next week.