Lil Peep's cause of death revealed to be an accidental overdose

Rapper and YouTube star Lil Peep has died aged 21. Photo / Getty Images

Lil Peep, who died on November 15 aboard his tour bus in Arizona, accidentally overdosed on Fentanyl and Xanax, a medical examiner's report has concluded.

Lil Peep, whose real name was Gustav Ahr, was widely believed to have died of a drug overdose but some suspected something sinister.

A series of private messages between Lil Peep and a 20-year-old fan called Mariah Bons emerged after Ms Bons allegedly boasted about getting him "high af" during a visit to their tour bus hours before he died, reports news.com.au.

"GBC [Lil Peep] high af because of me and my friend lol," one message from Ms Bons read.

"He passed the f**k out my brother called and I tried to get him to say hi to my brother but he wouldn't wake up."

Lil Peep apparently also tested positive for marijuana, cocaine, and Tramadol and a number of other powerful prescription opiates, according to the toxicology report, which was issued by the Pima County Medical Examiner and obtained by the Daily News.

No alcohol was detected in his system.

His brother, Oskar Ahr, said he believed Lil Peep's death was an accident.

"We have heard there was some sort of substance he did not expect to be involved in the substance he was taking," he told People last month.

"He thought he could take what he did, but he had been given something and he didn't realise what it was."

Lil Peep was one of the pioneers of "cloud rap", a genre of music dominated by ambient beats and emotional lyrics battling tough topics such as drug abuse and suicide.

He made no secret about self-medicating to quell chronic depression, anxiety and suicidal thoughts.

Rapper Lil Peep, aka Gustav Ahr, had a hit with Come Over When You're Sober. Photo / Getty Images

The son of Harvard-educated parents, Lil Peep moved to Los Angeles to pursue his music career at age 17 and quickly built up a devoted fan base.

His best known song was Star Shopping.

On the day of his death, he wrote on Instagram: "When I die You'll love me."