The singer wrote the song "Unforgettable" two days after a friend lost his battle with addiction.

Demi Lovato has dedicated their latest single, "Unforgettable (Tommy's Song)," to a friend lost to addiction.

The singer posted a heartfelt message on Twitter honoring Tommy Trussell III.

"Two years ago I lost someone who meant so much to me. His name was Tommy and he was such a beautiful, special man," they wrote. "I wrote this song the day after I found out that he had lost his battle with addiction. This disease is extremely cunning and powerful..."

Upon his death, the Camp Rock star posted a photo of the late model on Lovato's social media with a caption laced in heartbreak and pain over the loss of their friend.

"Devastated. Please hold your loved ones tight. Tell them they are special and that you love them," Lovato captioned a photo of the late model. "Make sure they know it. RIP to my boo."

The Grammy Award nominee also announced that all net proceeds of the song would be donated to the Voices project Founded by Ryan Hampton.

"If you know anyone who is struggling, please call 1-800-662-HELP," they added.

Lovato opened up about their own struggles with substance abuse in April with the release of a two-part album, Dancing With the Devil, that talks about their 2018 overdose.