Michael Jackson reportedly had a secret medical implant to help him battle addiction to prescription drugs.

The 'Beat It' hitmaker - who died in June 2009 after being administered a lethal dose of Propofol by his doctor, Conrad Murray - was allegedly fitted with the device, which effectively makes drug taking pointless by blocking pleasure receptors in the brain, in 2003 to stop him getting enjoyment from opiates.

The implant - which gave Michael doses of Narcan, the trade name for Naloxone, which is usually prescribed for heroin or morphine addicts - was discovered in the singer's body after he passed away but has come to light in court papers revealing evidence from one of his former doctor's, David Fournier, The Sun newspaper reports.

The papers state: ''Fournier believed Jackson had deceived him by not telling him about a 'Narcan implant' Jackson had inserted before a surgical procedure Fournier was helping with.''

His testimony is expected to be vital in Michael's mother Katherine Jackson's $40 million wrongful death lawsuit against AEG Live.

Katherine, 82 - who acts as a guardian for the King of Pop's children Prince Michael, 16, Paris, 15, and Blanket, 11 - accuses the concert promoter of being responsible for negligently hiring Murray, who is serving four years in jail on an involuntary manslaughter charge, to care for Michael as he prepared for his 50-date 'This Is It' tour. AEG's lawyers deny the claims.

The trial, which is being held at the LA Superior Court, is expected to last up to three months.