Melissa Etheridge's son Beckett Cypher has died at the age of 21 following a battle with opioid addiction.

In a statement released on Wednesday evening, the singer revealed her heart is broken but she'll use music to heal.

"Today I joined the hundreds of thousands of families who have lost loved ones to opioid addiction," Melissa wrote. "My son Beckett, who was just 21, struggled to overcome his addiction and finally succumbed to it today.

"He will be missed by those who loved him, his family and friends. My heart is broken. I am grateful for those who have reached out with condolences and I feel their love and sincere grief.

"We struggled with what else we could have done to save him and in the end, we know he is out of the pain now. I will sing again, soon. It (music) has always healed me."

Beckett was the 58-year-old's son from her romance with Julie Cypher. He and his older sister Bailey were the biological children of rocker David Crosby, who helped Melissa and Julie realise their dreams of becoming parents.

David responded to news of Beckett's death on Twitter on Wednesday, as he replied to a tweet from a user which alleged he "played no other part" in the youngster's life other than being a sperm donor.

"Not true," he responded.

Melissa is also mum to 13-year-old twins, Miller and Johnnie, from her relationship with Tammy Lynn Michaels.