Kira Kerkorian and Lisa Bonder. Photo / Supplied

Kira Kerkorian Bing might be the unluckiest heiress alive.

Despite having a claim to the inheritance of her two multi-millionaire fathers, she has largely missed out on both fortunes.

Earlier this week, Kira, 23, lost her court appeal for the US$451 million (NZ$645m) owed to her in the will of her late father, multi-millionaire US businessman Steve Bing.

For many years it was mistakenly believed Kira was the daughter of another multi-millionaire, US media mogul Kirk Kerkorian, which was another inheritance she was cut out of.

In June last year, her real father Bing, aged 55, died by suicide, leaving his fortune to his two estranged children, Kira Kerkorian Bing and Damian Hurley.

Kira is the child of Bing and former tennis pro Lisa Bonder, while her half-brother Damian Hurley, 19, is the son of Bing and English actress Liz Hurley.

Kira was gunning for the role of administrator of Bing's estate, which was worth US$451m, while Damian was due US$330m from his will.

However, in a strange twist, both kids won't get a cent of their father's fortune.

On Monday, the two half-siblings lost a court appeal.

The grandfather of Kira and Damian, Dr Peter Bing, had been fighting hard to keep them away from the money.

Dr Bing didn't want his "illegitimate" grandchildren to get the family fortune.

Now, the money will be split between the two children of Steve's sister Mary, who were born in wedlock.

The money was first put into a trust in 1980, with the intention that the trust "would not benefit any person born out of wedlock unless that person had lived for a substantial period of time as a regular member of the household".

Both Kira and Damian Hurley were not regular members of their father's household.

Liz Hurley fell pregnant with Damian Hurley in 2001 after a brief fling with Steve Bing.

Lisa Bonder was married to another man, Kirk Kerkorian, when she realised she was pregnant with Kira.

For many years it was widely believed Kira was Kerkorian's child.

Only later in life was it revealed that Bing was her biological father.

After Bonder and Kerkorian divorced, he paid a whopping US$100,000 a month in child support.

But Kerkorian suspected Kira wasn't actually his child – and in the noughties his private detective, Anthony Pellicano, famously swiped a piece of dental floss used by Steve Bing, a former boyfriend of Bonder.

Following DNA testing, that tiny strand proved that Bing was in fact Kira's father and, despite Kerkorian's estimated US$4.2 billion fortune, she inherited just US$8.5m when he died in 2015 at the age of 98.