Singer Demi Lovato "can't believe" that her father, Patrick Lovato, has been dead for a year.

The 21-year-old singer, who was devastated when Patrick Lovato passed away on June 22, 2013 after battling cancer, posted a touching tribute to him on mirco-blogging site Twitter Friday, reports contactmusic.com.

''Can't believe it's already been a year.. Wish I could've hugged you one last time.. RIP Daddy, I love you,` she tweeted.

She also posted a collage of photographs of herself and Patrick from when she was a little girl.

Lovato previously admitted laying her dad to rest was ''the hardest thing'' she had ever done, but felt an ''overwhelming sense of peace'' after his funeral.