Tech billionaire Elon Musk's estranged father has had a baby with his own stepdaughter who is 42 years his junior, MailOnline can reveal.

The extraordinary revelation could provide the truth behind the bitter family feud that has engulfed one of the world's richest families.

Errol, 72, was branded 'evil' and 'a terrible human being' by the Tesla Motors chief, who said his father had done 'almost every evil thing you can possibly think of'.

Now MailOnline can reveal that South African businessman Errol has fathered a 10-month-old baby son by his stepdaughter Jana Bezuidenhout, 30, who was four when he married her mother.

In a sensational interview with MailOnline, Errol said he could 'barely remember Jana's mother Heide, despite the couple being married for 18 years and having two children together.

Billionaire Elon Musk's estranged father has had a baby with his own stepdaughter who is 42 years his junior, MailOnline can reveal

Errol Musk, 72, father of the Tesla Motors chief, has a 10-month-old baby boy called Elliot Rush Musk with his stepdaughter Jana Bezuidenhout, 30 (pictured)

Jana (pictured) was four years old when Errol married her mother, Heide. Errol's relationship with Jana is said to be one of the reasons he is estranged from his billionaire son, Elon

Jana is pictured here last year with her mother Heide cradling Elliot Musk, who is the baby son of her former husband and her daughter. Next to them is her daughter with Errol, Asha Muak

Elon Musk stands beside a rocket on March 19, 2004 in El Segundo, Los Angeles. He is worth £20 billion and launched a Tesla car into space - but has not spoken to his father for 18 months

Errol is pictured here holding his son Elon as a baby. He says he gave Elon and his two siblings a luxury upbringing in Pretoria before Elon earned his first billion dollars at the age of 30

Elon, the 46-year-old SpaceX founder who has a £20 billion fortune, reportedly went 'berserk' when he learned that his step-sister Jana, who lived with him as a youngster, was having his father's child.

Jana, a mother-of-two, declined to talk about the highly unusual family set up when approached by MailOnline.

But a source close to the family confirmed Errol is the father of her baby boy Elliot Rush Musk.

Elon Musk poses for a portrait at in Los Angeles, California on July 25, 2008

They told MailOnline: 'Errol has known Jana all her life. It has split the family. Errol got married to her mother when Jana was four years old.'

Asked to confirm that Errol was the father of Jana's baby, the relative replied: 'That's correct.'

They said the birth had created a 'delicate situation' within the family as Heide was trying her best to support her daughter while keeping the identity of her little grandson Elliot Rush's father a secret.

'There is not a lot of people who know this. We would actually like the facts to come out,' they added.

Another relative told MailOnline: 'Errol got Jana pregnant. He is the father of her baby boy. But he was a father to her.

'The whole family was outraged when we found out. This is the reason why Elon is so angry with Errol. He is the only father she has ever known. And now he is the father of her child as well.'

For his part Errol, a successful consulting engineer, who lives in Langebaan, South Africa, revealed that a DNA confirmed he is the father of baby Elliot.

Though not discussing the family connection, he told the Mail on Sunday: 'I got my 30-year-old girlfriend Jana pregnant and we had a baby, who is now ten months old.

Elon Musk is pictured with ex-girlfriend Amber Heard. Errol said he thought Elon was emotionally fragile when he called him 'evil' and 'a terrible human being' in a recent interview

Elon is pictured with his mother Maye Musk at the 2017 Vanity Fair Oscar Party. Errol had three children from his first marriage to the model and socialite Maye, his High School sweetheart

In this picture Errol poses with his stepdaughter Jana (far left), her mother Heide Musk and their two daughter Alexandra and Asha (far right)

'Of course I love him dearly, even though it wasn't planned. In my own cautious way I insisted on a DNA test to ensure he was mine. '

'I told my daughter Ali about him because I thought she would be supportive and understanding. She said I was insane, mentally ill. She told the others and they went berserk. They think I’m getting senile and should go into an old age home, not have a life full of fun and a tiny baby.’

When the question was put to him Errol did not deny that his '30-year-old girlfriend Jana' is actually his step-daughter who he raised as his own child as a toddler, when challenged by MailOnline this week.

He replied: 'I have been single for 20 years. I have no step-daughters or step-sons. I have four ex-wives.'

Errol claimed he 'can hardly remember Heide' and wouldn't recognise his second wife if he saw her in the street – even though his former wife lives in the close-knit community of South Africa's affluent western Cape.

He told MailOnline: 'Heide and I were married for a very short time.'

In a recent interview Errol (pictured) admitted that his 30-year-old girlfriend 'Jana' had given birth to his baby, although he failed to disclose that she was his stepdaughter

Jana, who lived with Elon when she was growing up, has battled drug addiction and was forced to bring up her first child, a little girl called Emily, on her own

Jana proudly pats her pregnant tummy during her first pregnancy with her daughter Emily in 2013

Jana poses happily for the camera with her two half sisters Asha Musk (left) and Alexandra Musk (right), who are Errol and Heide's daughters and Elon Musk's half sisters

A craggily good-looking man with a 1,000-watt smile and an easy humour, Errol still flies his own plane up the spectacular West Coast and has a fishing boat parked in the garage next to his silver Bentley Continental.

He refused to acknowledge that it was his relationship with his stepdaughter that had led to the rift with son Elon.

He said: 'I do not know what Elon's anger is caused by. It has been ongoing since we left the USA against his will in 2003.'

Heide, his second wife, was a widow with three young children when she met Errol.

Her first husband Jock Bezuidenhout died in a car crash and Errol helped raise her little ones Jock junior, Jana and Harry.

Errol already had three children of his own from his first marriage to High School sweetheart, the model and socialite Maye Haldeman – Elon, his brother Kimbal and sister Tosca.

He talks about spoiling his children and bringing them up in luxury. Musk senior was a millionaire before the age of 30.

‘I drove them to school in a convertible Rolls-Royce Corniche, they had thoroughbred horses to ride and motorbikes at the age of 14. They were spoilt, I suppose. Maybe that’s why Elon is acting like a spoilt child now,’ he says.

Elon has described this childhood as ‘painful and isolated’, overshadowed by an absentee father who derided his eldest son’s budding scientific brilliance.

Jana, who lives just outside Cape Town, poses with her half sister Alexander Musk in a family picture. Jana refused to discuss the unusual nature of her relationship with her stepfather

A family source said of Jana: 'Errol has known Jana all her life. It has split the family. Errol got married to her mother when Jana was four years old.'

Another relative told MailOnline: 'Errol got Jana pregnant. He is the father of her baby boy. But he was a father to her.'

Errol and Heide had two daughters called Alexandra 'Ali' Musk and Asha 'Rose' Musk.

Elon and Kimbal came to live with their father and Heide in their sprawling and well-equipped home in Pretoria, where the couple made no distinction between children and step-children.

Shortly before his 18th birthday Elon left South Africa to go to university in Canada, where his mother's family came from before moving to the USA aged 24.

He encouraged his father to move to Malibu, California, and Errol, Heide, Jana and the rest of the children set up home there shortly after Elon made his multi-million-dollar fortune from the sale of PayPal in 2002.

Errol recalls feeling like a prisoner as he and Heidi plotted their escape, making secret appointments with the South African embassy to secure temporary passports before they fled back to South African in 2003 under a cloud.

Errol and Heide split up soon after and Jana and the other children were taken into the care of others.

Though naturally slim and blessed with piercing green eyes Jana has led a troubled life. She has battled drug addiction and was forced to bring up her first child, a little girl called Emily, on her own.

By contrast Errol is described as a doting father to Jana's latest baby, supporting them both financially and emotionally.

Elon is pictured with Peter Thiel in October 2000. By 2002, Elon had already made his first billion dollars from creating the PayPal internet payment system

Elon Musk’s SpaceX Falcon Heavy rocket takes off last month at the Kennedy Space Center in Florida

But despite his newfound love for his baby son, it has splintered one of the world's wealthiest families.

Elon, the space explorer who has started no fewer than four billion dollar businesses told American Rolling Stone magazine of his anger.

‘He was such a terrible human being, you have no idea,’ he told the interviewer with tears running down his face.

‘My dad will have a carefully thought-out plan of evil. He will plan evil. Almost every crime you can possibly think of, he has done. Almost every evil thing you could possibly think of, he has done. It’s so terrible, you can’t believe it.’

The two men - whose egos clashed while Elon was growing up - have not spoken for 18 months.

'It is difficult to see how Elon will ever be able to forgive his father for what has happened. The family is split down the middle and we don't know how it will recover.'