Demi Lovato thanked her fans for support after her biological father, Patrick Lovato, died of a heart attack on June 22, 2013.

Even in her grief, Demi Lovato is counting her blessings. The singer and X Factor judge, 20, quietly acknowledged the death of her father Patrick Lovato with a thankful tweet late Sunday, June 24. "I feel so humbled to have had so much support from my fans, friends, family and complete strangers," the former Disney star wrote to her 15 million-plus followers. "God bless you all, thank you so much love."

Her rep previously confirmed Patrick Lovato's death to Us Weekly; the "Heart Attack" singer did not attend X Factor auditions over the weekend as she mourned her father, who had been battling cancer for many years.

It's not known whether father and daughter reunited before his death; they had been estranged for many years. "The last time I talked to him was two years ago," Lovato said in 2009. "When somebody lets you down after you've been the only one there for them, and so many times, you don't know what else to do."

She sang about the difficult relationship in her song "For the Love of a Daughter" from her 2010 Unbroken album.