Michael Jackson's doctor is set to seek custody of his two eldest children.
Dermatologist Dr Arnold Klein has reportedly told pals he is the father of Prince Michael, 12, and Paris, 11, and is ready to take responsibility for them.
A source said: "Arnold is planning to fight for custody of Prince Michael and Paris. He says he can prove he is there father.
"Arnold has told his close friends he is Prince Michael and Paris' father for years, while never giving a straight answer in public.
"He says he was paid nothing for the sperm but was paid for keeping the information confidential."
Speculation has been rife that Klein is the biological father of the children since Jackson passed away from a suspected cardiac arrest last month.
Klein - who was the boss of nurse Debbie Rowe, Jackson's ex-wife and the mother of the two children, when she met the late pop icon - has failed to deny the claims outright.
Speaking on US TV show 'Good Morning America' earlier this month, he said: "I can't say anything about it, but to the best of my knowledge, I am not the father of these children.
"I can't answer it in any other way. I don't want to feed any of this insanity that's going around."
Speaking on another TV programme, Klein admitted he had donated to a sperm bank but claimed to be unaware whether Jackson had used it to father Prince Michael and Paris.
Jackson is said to have asked Klein to father the children because he was so impressed with how intelligent he was.
The source added to Britain's Sunday Mirror newspaper: "Arnold is brilliantly clever. He has a photographic memory and instant recall."
Jackson's mother Katherine Jackson currently has temporary custody of Prince Michael, Paris and Michael's youngest son seven-year-old Prince Michael II, also known as Blanket.
A custody hearing was due to take place on Friday but has been postponed until August 3.
Mrs Jackson is seeking full custody of the children, but her lawyers are believed to be discussing the matter with Debbie Rowe, who is understood to want access to Prince Michael and Paris.
Meanwhile, it has been claimed Jackson's death could soon become a murder investigation.
Los Angeles police have reportedly already told Jackson's family - including sister La Toya, who recently insisted Michael had been murdered - they will be pressing charges imminently, which could lead to a trial.
Friend of the Jackson family Terry Harvey told Britain's News of the World newspaper: "The autopsy shows that Michael died of a drug overdose with Diprivan and a range of pills in his stomach. He had needle marks on his neck and all over his body.
"The authorities have told the family the Drug Enforcement Administration (DEA) are pushing for a criminal charge.
"It is likely to be second-degree murder, due to the actions which led to his death. They have been assured that someone, or maybe more than one person, will be brought to trial.
"The family are working with the DEA and Los Angeles Police Department (LAPD) to work out which doctor prescribed Michael these drugs and how far back this serious problem runs."
Diprivan is also known as Propofol, and is used to put people to sleep before surgery.
Terry also claims the Jackson family may sue concert promoters AEG - who were behind Michael's comeback shows in London - for "wrongful death".
Referring to Michael's father Joe, Terry said: "Joe Jackson has made no secret of his efforts to step in to get Michael to rehab while he prepared for his London shows. The question is how much did the
concert organisers know about his drug problems and who was feeding him the drugs?
"I can see Joe filing a lawsuit against anyone who is found to have caused fatal harm to his son."