The implant was found in the King of Pop's body after he died but has just come to light in explosive newly released court papers.
The papers contain evidence from one of Jackson's former doctors, Beverly Hills anaesthetist David Fournier, who treated him in the 1990s and early 2000s."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," the papers state.
His testimony will be key evidence in the 26 billion-pound civil trial brought by Jackson's mum Katherine and his kids against concert giant AEG.
The Jacksons wanted the implant evidence thrown out but were overruled by the judge.