Demi Lovato took to Instagram to pen a sweet message to her late father, Patrick Lovato, who passed away in 2013 after battling cancer. The "Confident" singer posted an adorable throwback photo with the caption: "My guardian angel gave me a sign today. Thanks, Dad. I love you too." Though Demi didn't reveal exactly what the sign in her heartfelt message was, she's always been very open about dealing with losing her father and his struggle with mental illness, so her fans were quick to send love in the comments. Her guardian angel has a lot to be proud of, because Demi is killing it lately — her new single made it to No. 1 on the Billboard + Twitter Trending 140 chart, and she totally rocked the iHeartRadio Music Festival with her support system, Wilmer Valderrama and Nick and Joe Jonas, close by. Keep scrolling to see the sweet Instagram photo, then fall in love with Demi's new puppy.