The US X Factor judge, who has been estranged from her biological father since 2007, took to Twitter for the first time last night (23 June) since the news broke.
She said: "I feel so humbled to have had so much support from my fans, friends, family and complete strangers... God bless you all, thank you so much."
A rep for the singer confirmed Patrick's death after Demi's older sister Dallas tweeted, "Rest in peace daddy I love you." Meanwhile fans instantly showed their support by trending #RIPPatrickLovato on Twitter.
Demi's mother Dianna De La Garza, who divorced Patrick in 1994, also wrote, "Thank you all for the outpouring of love and prayers. Y'all are amazing."
Details of the circumstances surrounding Patrick's death have yet to be released.
Following the news, Demi did not appear alongside her X Factor team for a photo shoot. Sending his condolences to Demi, Simon Cowell said: "My thoughts are with you Demi. X."
Meanwhile show host Mario Lopez added: "My thoughts & prayers are with you @ddlovato ... God bless you & your family. #StayStrongDemi."