SIR Elton John's ex manager and lover John Reid is threatening to cast a shadow over the pop superstar's 21 December (05) wedding to partner David Furnish, by releasing a tell-all autobiography about his time with the star.

Reid and John ended a tempestuous 28-year relationship in a messy 2000 court case when the rocker attempted to recover $25.2 million (GBP14 million) he claims he was owed by one of Reid's former employees.

The battle lost him $14.4 million (GBP8 million) in legal fees and exposed his extravagant lifestyle to the public, including the staggering $72 million (GBP40 million) John spent in a 20 month period.

More details about their partnership will enter the public domain if Reid carries out his threat and publishes the memoir.

He recently said of the rocker - who will marry Furnish when gay civil partnerships become legal in Britain - "(He is) a modern day potentate - everything revolves around him."