Los Angeles - The tussle for control of Michael Jackson's children and estate took on some new twists Tuesday as reports surfaced that he was not the biological father of his three children.

On the question of his estate, The Wall Street Journal reported that a lawyer who had recently been rehired by Jackson was in possession of a will signed by the superstar in 2002.

Celebrity website TMZ. com and gossip magazine Us Weekly both reported that neither Jackson or his ex-wife were the biological parents of the two children born during their marriage: Michael Joseph Jackson Jr, known as Prince Michael, 12, and Paris Michael Katherine Jackson, 11.

His third child Prince Michael II, 7, was also conceived outside the womb, was delivered by an unknown surrogate mother and is also not Jackson's biological child.

Us Weekly reported that the father of Jackson's two children is his dermatologist Arnold Klein, who has also been identified as a potential source of the prescription medications that have been linked with his death.

The reports came as The Wall Street Journal revealed that a will drafted by Jackson in 2002 divides the singer's estate among his mother, three children and one or more charities. The paper said that a lawyer for the pop singer could submit the will, believed to be his last, to Los Angeles Superior Court as soon as Thursday.

On Monday a judge granted temporary guardianship of the three children to Jackson's mother, Katherine Jackson, 79, but scheduled a further hearing for next Monday on her request to become their permanent guardian. She has also filed a petition to be named the executor of his tangled but valuable estate.

The assets in Jackson's estate are valued at over 1 billion dollars, though he had amassed more than 400 million dollars in debt. The value of his estate is likely to soar in the coming years as fans flock to buy his records and other merchandise associated with the former King of Pop.

Jackson had 13 of the top 20 selling albums on iTunes Monday and 40 of the top 100 songs.(dpa)