Demi Lovato's father, Patrick Lovato, has died.

Demi Lovato, 20, has been estranged from her father since 2007. Demi agnowledged the death of her father Patrick Lovato on Twitter, saying, "I feel so humbled to have had so much support from my fans, friends, family and complete strangers," the singer wrote. "God bless you all, thank you so much love."

Demi Lovato, an X-factor judge and former Disney star, said about her father,

"The last time I talked to him was two years ago," Lovato said in 2009. "You try to have faith in somebody, even when you're the last person that believes in him. But 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."

"I had to cut off all connection," the Skyscraper singer added. "It was hurting me too much."

Patrick Lovato battled cancer for years. During a 2011 interview, he said that he was trying to reach out to his daughter. "It is not like I want anything from her, all I want is her love," he said.

It is not known if Demi and Patrick Lovato reconciled before his death.

Demi Lovato sang about her relationship with her dad on the song "For the Love of a Daughter" from her 2011 album, "Unbroken." The song hinted that Lovato's father may have had problematic relationship with alchol.

Lovato missed  an X-Factor photoshoot over the weekend.Lovato judges the singing competition "X Factor" with co-judges Paulina Rubio, Kelly Rowland, and Simon Cowell.

Lovato's sister, Dallas Lovato, 25, first Tweeted the news.

Lovato's fans made #RIPPatrickLovato a trending topic.