Michael Jackson owed nearly $500 million in debt before he died.

The 'Thriller' hitmaker was forced to fork out $30 million-a-year in interest charges after his wild spending on lavish furniture and bizarre artwork spiralled out of control, and his previous tours failed to bring in any profit to cover it, forensic accountant William R. Ackerman has told the court.

Ackerman was called to testify on behalf of concert promoters AEG Live in the wrongful death lawsuit filed by the Jackson family on Monday (12.08.13), where he told jurors how the late singer would regularly splash out on travel, donations to charity, gifts and ''a lot of money of jewellery''.

He explained: ''He spent more than he brought in. Consistently, his largest expenditure was interest expense. He spent a ton of money on interest.

''On an annual basis [he was] spending 15 to 20 million dollars a year more than he brought in.''

However, Michael's Neverland Ranch - where he lived from 1988 to 2005 - and private amusement park was also putting a strain on the star's pocket as it required maintenance staff for the petting zoo and the train travelled around the property.

Banks and credit companies refused to provide the 'King of Pop' with any more cash loans after 2007, which meant mortgage payments on his mother Katherine's family home were not met.

Ackerman told the Los Angeles court: ''He was tapped out.''

The Jackson family are suing AEG Live as they believe the company negligently hired and supervised Dr. Conrad Murray - who is currently serving four years imprisonment for involuntary manslaughter - who administered the lethal dose of Propofol, which killed Michael in 2009.