Prince had the painkiller Percocet in his system when he died.
The 'Purple Rain' hitmaker's autopsy has reportedly discovered the late legendary singer had the highly-addictive drug, which contains acetaminophen and oxycodone, in his body when he was found dead at his Paisley Park estate in Minnesota on April 21, according to the Minneapolis Star Tribune newspaper.
However, it's not yet known if the drug, which he was believed to be on to help cope with his chronic hip pain, caused his death.
The claims come just a few hours after it was revealed Prince had tragically died the day before he was due to meet with a doctor about his addiction to painkillers.
The 57-year-old musician's representatives called Dr. Howard Kornfeld, a national authority on opioid addiction treatment, on April 20 and asked him to go to Prince's home in Minneapolis because they were "dealing with a grave medical emergency".
While Howard could not travel from California immediately, he sent his son Andrew to go ahead and speak to Prince about his problem before he flew out the following day.
However, when Andrew arrived at Prince's estate on April 21, he was nowhere to be found and he and two of the star's employees eventually found him unresponsive in an elevator.
Meanwhile, the week before his death, the singer was rushed to hospital in Moline, Illinois, for a "save shot", which is administered to counteract the effects of opiates, after being taken seriously ill on his private jet on the way back from a gig in Atlanta.
The investigation into his death is still ongoing and now the federal authorities have jumped onboard the case to help determine whether Prince died from an overdose and, if so, who administered him the drugs in the first place.