The singer shared somber news on Instagram.
Demi Lovato is sharing more sad news on Instagram.
WATCH: Demi Lovato's Moving Tribute to Dog: 'This Has Been the Most Painful Week of My Life'
The 23-year-old singer posted a heartfelt tribute to her late grandfather on Monday, which included a sweet message to the adorable puppy that she and boyfriend Wilmer Valderrama lost in a tragic accident in July.
"My two favorite Buddy's are now playing in Heaven," the actress captioned a photo of her grandfather and the adorable pup. "My heart is absolutely broken and I can't even begin to imagine a world without my Papa but I know one day we'll meet again and that's what keeps me going."
WATCH: Demi Lovato 'Would Say Yes' If Wilmer Valderrama Proposed
"I hate writing this," Lovato continued. "But RIP Papa... I miss you so much already. I love you. Please keep my Mimaw in your prayers."
Lovato asked for prayers for her "Papa" in another Instagram post back in June, just before Father’s Day.
PICS: Wilmer Valderrama Shares Hilarious TBT in Support of Demi Lovato
The actress thanked her fans for helping her and Valderrama through their difficult summer.
"We can’t thank you all enough," she captioned an emotional collage after their puppy died in late July. "This has been the most painful week of my life but Wilmer [Valderrama] and I had so much love and support, I’ve been able to stay strong and will continue to get through this difficult time."