Grammy-winning singer-songwriter Melissa Etheridge has announced that her 21-year-old has son died following a struggle with opioid addiction.

The star, best known for songs including Aint It Heavy and Come To My Window, wrote a tribute to Beckett Cypher, one of her two children with former partner Julie Cypher, on Instagram.

He had struggled with opioid abuse and died on Wednesday.

Etheridge said she had joined “the hundreds of thousands of families who have lost loved ones” due to opioids in the US.

“My son Beckett, who was just 21, struggled to overcome his addiction and finally succumbed to it today,” she said. “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 struggle with what else we could have done to save him, and in the end we know he is out of the pain now.”

Etheridge added: “I will sing again, soon. It has always healed me.”

The 58-year-old and Cypher, who broke up in 2000, also have a daughter, Bailey.

Both children were conceived using artificial insemination and the sperm donor was later revealed to be singer David Crosby, 78, who retweeted a tribute.

He also replied to one Twitter user to say it was “not true” that he was simply a donor and “played no other part” in raising Beckett.

Etheridge and Crosby discussed their arrangement during a TV interview in 2000.

“I do not believe that my children will be wanting in any way because they didn’t have a father in the home every single day,” Etheridge said.

“What they have in the home is two loving parents. I think that puts them ahead of the game.”

The opioid crisis in America has been linked to more than 400,000 deaths over the past two decades.

An opioid is a drug that acts on parts of the brain and body, called opioid receptors, which help moderate sensations such as pain, mood, appetite and various bodily functions.

Opioids exist in nature – for example in the form of opium – and have been used for thousands of years by humans, who have gradually refined them into other forms like codeine, heroin or morphine.