MICHAEL JACKSON has demanded nine doctors on-hand at a forthcoming private gig in case he falls ill during the comeback performance, according to the singer's biographer.

The Thriller singer has reportedly agreed to sing at a party for Russian billionaire eg Derispaska in April in exchange for $2.9 million.

And in his contract, the star has stipulated he must have a full team of experts to ensure he is in full health, according to Ian Halperin, author of forthcoming book Unmasked, The Michael Jackson Story.

If the small-scale show is successful, it could mean Jackson will go ahead with plans for a rumoured residency at London's O2 Arena - his first major performances since his last tour in 1996.

Halperin says, "The concert would be his first in years and is being seen as a test to see if he could perform in London but a lot depends on his health.

"The rider for the gig by Jackson's handlers includes a request for nine top doctors to be on site at all times, 11 gourmet chefs, 1,200 bottles of the world's finest bottled water, Bling H2O, and six massage therapists."