Michael Jackson's family claim AEG Live hired a lookalike to promote his final shows.

The 'Thriller' singer's family are convinced the concert promoter - who they are suing for $40 billion damages in a wrongful death lawsuit - hired a body double to appear in public and promote the ailing star's 'This Is It' residency at The O2 in London in the run up to his death in June 2009.

A source told The Daily Star newspaper: ''Paris and Prince and their grandmother believe a fake Michael was involved. They have hired detectives to track him down.''

Michael's mother Katherine Jackson, as well as his children Paris, 15, and Prince Michael, 16, believe the double was used at The O2 arena when his concert dates were first announced in 2009.

They also think the imposter featured in video clips showing the late King of Pop rehearsing for his farewell tour, claiming Michael was not fit enough to execute the dance moves.

The Jacksons are embroiled in a legal battle against AEG Live, who they claim ''negligently'' hired doctor Conrad Murray, the disgraced physician responsible for administering the lethal dose of Propofol which killed the superstar.

They have allegedly hired detectives to find the double and force him to give evidence in court.

Bianca Cobb, a body language expert, told Fox News: ''In my opinions, the man in the clips isn't Michel Jackson. The walk is cockier and had more bounce than MJ's typical stride. He tended to walk with his head down.''

AEG have denied the claim, while Sony - who released his 'This Is It' movie - insisted: ''Every frame is undeniably Michael.''