Michael Jackson's former doctor has denied he is the father of the late singer's two oldest children – as far as he knows.

Dr. Arnold Klein – whose former assistant Debbie Rowe was married to Michael for three years and is the mother of Prince Michael, 12, and 11-year-old Paris – refused to give a definite answer about the paternity of the kids when quizzed.

Klein, who was Michael's dermatologist for 20 years, told US TV show 'Good Morning America': "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.

"I will tell you one thing, these are brilliant children and I want them in no way to be harmed.

"These are great, wonderful, fabulous children who he loved deeply."

Although Michael – who died last month after a suspected cardiac arrest – always insisted he was the biological father of Prince and Paris and claimed they were conceived in the 'natural' way.

However, Debbie – who was working for Klein in his Beverly Hills clinic when she met Michael – has previously alleged the children were created by artificial insemination, and the sperm used was not the 'Thriller' singer's.

It had been rumoured Klein – who spent last Christmas with Michael and his family – had donated his sperm so Michael could fulfil his lifelong dream to become a parent.

Debbie gave up custody of Prince and Paris following their divorce in 1999 and Michael went on to have another child, Prince Michael II – also known as 'Blanket' – via a surrogate mother, whose identity has never been revealed.

Although Michael did his best to keep the children out of the spotlight – even making them wear veils on the rare occasions they ventured out in public – all three of them appeared on stage at his star-studded memorial on Tuesday (07.07.09).

Paris made an impromptu speech near the end of the ceremony, describing her dad as 'the best father you could imagine', and producers have denied it was scripted.

Ken Ehrlich, producer of the tribute, said: "It was not planned. A lot of the show was not scripted. Music was laid out, but most of the speakers really spoke from their heart – people who knew Michael well – and I think that's what gave the show its heart."