Jerry Oppenheimer is a New York Times Bestselling author whose latest book, The Kardashians: An American Drama, is released this week. In this exclusive story, he reveals the family's love-hate relationship with O.J. Simpson, and the surprising racial strife that also existed.

Since the inception of their reality TV series, the Kardashians' personal lives have been anything but private - including their high-profile, sometimes scandalous interracial relationships.

It was Kim's infamous sex tape with then-boyfriend Ray J that thrust her into the limelight a decade ago - which was preceded and followed by three turbulent marriages.

Khloe's sordid relationship with troubled NBA star Lamar Odom - who she married after one month of dating - made international headlines in 2015 after he was discovered drugged in a Las Vegas brothel.

And Rob Kardashian's bizarre entanglement with ex-stripper Blac Chyna was as far-fetched as any in La-La Land.

But the untold story I uncovered during two years of reporting for my book, The Kardashians: An American Drama, I reveal the clan's patriarch, attorney Robert Kardashian actually had serious issues regarding interracial marriage.

Robert Kardashian is said to have 'gone ballistic' after learning Kim eloped with her first husband Damon Thomas in 2000 because he preferred his daughter to date white men, according to The Kardashians: An American Drama

Kardashian reportedly became upset about his daughter's interracial relationship because O.J. - who he famously defended for the murder of Nicole Brown (pictured) - always bragged about 'getting white p***y'

He quietly blamed himself for bringing his close friend O.J. Simpson into his family circle, thus making his children 'too liberal' about race relations, according to a close friend.

Robert Kardashian had been furious when Kim married her first black husband, and because of prejudice he ended a secret love affair with a beautiful black attorney who served with him on the 'dream team' that got O.J. acquitted of murder in 1995.

In 2000, Kim secretly married music producer Damon Thomas, the first of her three African-American husbands, when she was 20 years old.

But according to a close friend of Kardashian, when Robert learned about the nuptials, he had 'gone ballistic -- upset and concerned about his daughter's interracial relationship.'

'I know these black guys and I've known them all my life, and I know they love white p***y,' Kardashian angrily told the friend.

'O.J. always brags about how much he and those guys get. The problem is my kids are liberal, maybe too liberal, and I have no one to blame but myself because I introduced them to Uncle O.J. and others, and they always felt comfortable with them.'

'It was my sense, my perception that Robert would have preferred Kimmy to be with a white guy,' the close friend said.

Kardashian's racial animosity came as a shock to his inner-circle because his closest friend for decades was O.J. - who he defended during the former football player's famous murder trial - and the two were considered brothers.

When O.J. was often on the outs with his first wife because of his womanizing with mostly young, white women, he roomed with Kardashian and Kardashian's older brother, Tom, in their Beverly Hills bachelor pad.

The two later became partners in a succession of unsuccessful businesses.

Kim's sex tape with then-boyfriend Ray J catapulted her into fame and infamy after it was leaked in 2007

The 36-year-old went on to have a string of interracial romances and dated NFL player Reggie Bush from 2007 til 2010 (pictured in 2009)

The mother of two finally settled down with Kanye West when the couple married in 2014

Kourtney, Kim, Khloe, and Rob called him 'Uncle O.J.,' and one of Kim's first acts as a newborn was to throw up on O.J.

Kris Jenner, pledged in a memoir that she always 'loved O.J.,' and Kris was so close to his late second wife, Nicole Brown Simpson, that she had the same breast implants to match Nicole's.

Now, years after Kardashian died of throat cancer in 2003, all but his first-born, Kourtney, had been publicly involved in mostly stormy interracial relationships.

Jerry Oppenheimer uncovers the family's untold stories based on two years of reporting in The Kardashians: An American Drama, released this week

A Kardashian insider told me: 'Robert would be rolling over in his grave. I think he firmly believed that the black guys he knew like O.J. strictly went after white women for sex, and that angered him.

'But Robert was definitely not a racist. He was a good Christian, a born-again Christian.'

The reason Kim kept her marriage to Damon Thomas a secret from her father, according to sources, was because of her anger at her dad for being part of the O.J. defense team.

Kim, her siblings and mother Kris, firmly believed O.J. had been Nicole Simpson and Ron Goldman's killer and were furious that Kardashian help get him acquitted.

They had cut virtually all ties with him.

He only learned about Kim's secret marriage when her older sister, Kourtney, squealed.

'Kim keeping her marriage a secret from her father was devastating to Robert, too. Robert was a traditionalist and really believed that his children had his confidence, and he had theirs. But he didn't,' childhood friend and one-time lover, Joni Migdal said.

With all the men of color in the lives of the Kardashian women along with their looks and lifestyle, they have become targets of criticism from some prominent African-Americans who have accused them of 'cultural appropriation' – of lifting black style for their own purposes, financial and otherwise.

Shanelle Matthews of the Black Lives Matter group declared that Kim Kardashian West has shown disrespect for the black community.

'Banking on blackness is a shameful enterprise, and the Kardashians are no better than racist judges, prison officials and corporations who make money off of the incarceration of black bodies.'

She further charged that the Kardashians know nothing about being black 'all the while trying to be black, such as Kim showing off her huge a** in tight clothing,' she said.

Robert's own racial biases led him to the end of his secret romance with a black lawyer.

Kardashian had suddenly fallen head over heels for Shawn Chapman Holley, the African-American attorney who was assisting lead attorney Johnny Cochran in O.J.'s race-card defense.

Kim, Khloe, and Rob have been known to have turbulent interracial romances over the years, and according to a close source, Robert Kardashian would be 'rolling in his grave'

Khloe tied the knot with NBA star Lamar Odom after dating for one month in 2009. Their sordid relationship made international headlines in 2015 after he was discovered drugged in a Las Vegas brothel

She was a member of his prestigious Los Angeles firm, the Law Offices of Johnnie L. Cochran.

The relationship was so intense that Kardashian even broke up with his beautiful, blonde and buxom live-in fianceé, Denice Shakarian Halicki, who was his third cousin.

Immediately after O.J. was acquitted, Kardashian was interviewed by Barbara Walters.

When she asked him what the impact of the trial had been on him personally he responded that its toll included the loss of Denice, suggesting that the strains and stresses of the trial had been too much for them to bear as a couple.

But he had lied to America's then-premier celebrity interviewer.

In the popular 2016 TV miniseries The People v. O.J. Simpson, Holley -- known as Shawn Chapman at the time of the actual trial – was played by the actress Angel Parker and Kardashian's character was played by the actor David Schwimmer.

But there was nothing about the lawyers' secret romance in the program or in the book, written by Jeffrey Toobin, on which the show was based. It had been kept top-secret.

Virtually everyday of the months-long trial, Chapman and Kardashian were together in the courtroom, in conference rooms, at evening and weekend meetings with the other lawyers, all working to get O.J. acquitted.

Despite his prejudices, Robert reportedly ended things with his beautiful, blonde and buxom fiancée, Denice Shakarian Halicki, after falling in love with a black woman

Robert had a secret affair with Shawn Chapman Holley (middle) who worked alongside the 'dream team' during O.J.'s murder trial

OJ Simpson defense lawyers (from left) Barry Scheck, Howard Harris, Shawn Chapman, Carl Douglas, Johnnie Cochran, Robert Blazier, Jo-Ellan Dimitrius (behind Blasier) and Robert Shapiro

As time passed, Kardashian was more than smitten, as Chapman was with him. Only a very few in Kardashian's close circle knew about their love affair.

'I am absolutely positive that Shawn would want that part of her life with Robert kept secret. It was a big secret, and they were very careful,' a source with knowledge of the romance told me.

Another close friend of Kardashian's, Larry Kraines, told me: 'Robert and Shawn were on the case together…and they began dating, and I got to know her well. She was very bright, very liberal…and that sort of broke up Robert and Denice.'

After Kardashian began seeing Chapman, Kardashian told Kraines: 'Other than the physical attraction, and being sweet and Armenian, I just don't see myself spending the rest of my life with Denice.'

Another friend said that Denice, 'did love Robert…the lifestyle…the house…the engagement…Denice didn't want to break up with Robert.'

Chapman did not respond to emails or phone messages requesting comment for my book about her relationship with Kardashian.

A source called their relationship 'a big secret, and they were very careful,' but the romance did not last (The two pictured visiting O.J. in jail)

Shawn Chapman Holley (left) and Robert continued their relationship a few months after he and Halicki split

Denice also declined to be interviewed. But Denice's mother said her daughter and Kardashian would 'have probably been married if it wasn't been for that murder trial because it just got over the top. It was such a drama.'

Not long after Denice left, Robert ended it with Shawn.

'Robert realized that because Shawn wasn't white that he couldn't get really serious with her, and that was the part where he had to give her up,' a Kardashian friend told me.

'Shawn was devastated because she really loved Robert, and I think he really loved her much more so than he loved Denice. Shawn was smart and lovely and a wonderful person.

'Robert told me he loved her but had to come to grips with his own biases – his racial biases. It didn't matter that his best friend had been O.J. He just knew he could never give Shawn a commitment the way she wanted it because of her race.'

Over the years since her break up with Kardashian, Shawn has become one of Los Angeles's power lawyers to the stars, and her connection with the Kardashian name continued.

When Kanye West got into a civil suit with a photographer, he hired her to defend him. Kim's one-time boyfriend Reggie Bush hired her, and other clients included Michael Jackson, Axl Rose, Snoop Dogg, and Lindsay Lohan.

O.J. had been a part of Robert Kardashian's life for decades, a brother-like relationship that ended with the double-murder acquittal.

Their friendship began in a popular Beverly Hills bar, The Luau, where they both hung out, and where the maître d' introduced them.

Kim reportedly kept her secret marriage from her father because she was angry she was defending O.J. Simpson, who she and her siblings believed murdered Nicole Brown Simpson and Ron Goldman (pictured)

Three years older, Kardashian, all of 5-ft-9, had idolized O.J. who was a star player at USC where Kardashian got his degree and had been manager of the Trojans football team.

The two bonded instantly, and were always together. At the Luau bar, Kardashian and O.J. hit on the pretty girls, and on one occasion Kardashian, trying to impress, told the women that he had been a hit man for the Armenian Mafia.

His family was in the meatpacking business and in the mid-1970s were targets of a federal probe into corruption in the meatpacking business in L.A.

O.J. and Kardashian were partners together in a number of businesses, none of which were very successful. The two jointly-owned a jeans boutique in trendy Westwood near the UCLA campus, but it didn't take off.

Coeds were more interested in meeting O.J. than in buying the denim goods. A frozen yogurt business was also a relative flop.

Kardashian later tried convincing movie theaters to play pop music by name stars, and O.J. was a partner in one of those operations. But it, too, didn't succeed.

After Tom Kardashian got in trouble in the meatpacking scandal, Robert, devastated by the scandal, became a born-again Christian, baptized in the Holy Spirit in the Pacific Ocean in July 1974. And one of those he soon tried to convert was his bosom buddy O.J. Simpson.

'As Bob would bring his dates to our church' – one of them was his girlfriend Priscilla Presley before he married Kris – 'he brought O.J.,' Kardashian's pastor Kenn Gulliksen told me.

A popular evangelical minister who had officiated at Robert and Kris's wedding, and had remained a lifelong friend, Gulliksen said that Simpson began coming to a weekly bible study that attracted a lot of people from the entertainment industry.

Rumors had circulated for years that Kris had had an affair with O.J. and that Khloe was O.J. biological daughter. But my investigation showed there's no truth to any of that.

However, sources close to Robert Kardashian told me that he was not her biological father, but that he loved the child and agreed to raise her as his own. Kardashian confided in his minister that he and Kris had not been having sex in the time frame when Khloe was conceived, and a close Kardashian friend told me that Kardashian refused to take a DNA test because he did not want a scandal at the time involving what was later revealed as Kris's cheating on him.

'O.J. always liked to be around celebrities, and liked their celebrity to rub off on him,' Gulliksen revealed in a series of interviews with me.

'For all O.J. had accomplished, he was insanely insecure, every week I would corner O.J., as often as I could and ask him, "Why is it that you haven't invited the Lord into your life?" And he finally answered me and he said, "I don't see any difference between Jesus and Buddha and these other guys."

'That was O.J.'s answer. But, he still came, I think, in deference to Bob.'

He soon came to think of the football hero as a 'narcissistic jerk and viewed him as a self-loathing black man who wanted to be white.

O.J. was his own God, in his own universe. Everything was about O.J. But his friend, Robert, was a 'true man of God.’