Emergency officials confirm they transported a 25-year-old woman who lives on singer Demi Lovato’s block to the hospital amid reports that the pop star suffered a drug overdose. Picture: Jordan Strauss/Invision/AP

Los Angeles - US pop music star Demi Lovato, who has spoken openly about her history of drug and alcohol abuse, was taken to a Los Angeles hospital on Tuesday suffering from a suspected overdose, according to media reports.

Representatives for Lovato, 25, did not respond to a request for comment but People magazine, quoting an unidentified source, reported she was "okay and stable."

The magazine later updated its account, quoting a source as saying the Grammy-nominated recording star was "awake and talking."

TMZ, quoting law enforcement sources, reported that Lovato was found unconscious at her home and was treated with Narcan, an emergency antidote for suspected opioid and drug overdoses.

Los Angeles police said they had responded to a medical emergency on Tuesday involving a woman on the Hollywood Hills street where Lovato reportedly has a home but declined to identify the person.

City fire department spokeswoman Margaret Stewart said a 25-year-old woman was transported to a local hospital from that location.

Lovato released a song last month called "Sober" in which she sang: "Momma, I'm so sorry, I'm not sober anymore, And daddy, please forgive me for the drinks spilled on the floor, To the ones who never left me We've been down this road before, I'm so sorry, I'm not sober anymore."

The New Mexico-born performer rose to fame on Disney Channel shows "Camp Rock" and "Sonny with a Chance" 10 years ago and forged a pop career with hits like "Skyscraper" and "Sorry Not Sorry."

In a 2017 YouTube documentary, "Simply Complicated," Lovato spoke about years of substance abuse, eating disorders, and drinking, saying she first started using cocaine when she was 17.

She entered rehab at the age of 18, where she was diagnosed with bipolar disorder.

Lovato, who has some 69 million followers on Instagram, was in the midst of a US tour and was due to perform in Atlantic City, New Jersey, on Thursday.

Her hospitalisation became the top trending item on Twitter on Tuesday, with fans and celebrities expressing concern and support.

Country singer Brad Paisley tweeted: "Addiction is a terrible disease. There is no one more honest or brave than this woman."