Rebecca Loos claimed she had an affair with the footballer when she worked as his Personal Assistant in 2003 in Spain.
Loos, 46, sold an exclusive tell-all interview to now defunct Sunday tabloid The News Of The World in 2004 for a six-figure sum.
The Beckhams have always dismissed the claims but no legal challenge was ever made.
Victoria confessed in the new documentary: "Up until Madrid sometimes it felt like us against everybody else but we were together, we were connected, we had each other. But when we were in Spain, it didn't really feel like we had each other either.
"And that's sad. I can't even begin to tell you how hard it was and how it affected me. It was a nightmare."
The Beckhams rode out the storm and have now been married for 24 years.
But what happened to Rebecca Loos?
Loos worked as David Beckham's PA and translator in 2003 when he was transferred from Manchester United to Real Madrid.
She told The News Of The World that they became close while spending a lot of time together when he first moved to Spain and his Spice Girl wife Victoria was at home caring for their two young sons Brooklyn and Romeo.
Loos claimed that while working with David they conducted a four-month affair before her contract was terminated. She sold her story to the tabloid in 2004.
David Beckham has always denied the allegations.
In the spotlight
Even back in 2003 The Beckhams were one of the most famous power couples in the world - as a Spice Girl and a former England football captain.
After Loos sold her story, she became a celebrity in her own right and was invited to movie premieres and showbiz parties.
As a model and socialite she was constantly gracing the pages of newspapers and magazines, and she made the most of the lads mag trend, posing for the covers of FHM, Playboy, Nuts and Zoo.
The pig issue
Off the back of her new found fame the reality TV offers started to flood in.
The first show Loos signed up to in 2004 was Channel 5 show The Farm, which followed a number of celebrities - including Paul Daniels and Debbie McGee, Jeff Brazier and Vanilla Ice - living on a farm together and taking part in agricultural work.
The Farm saw Loos achieve what has arguable become her second biggest claim to fame - when she masturbated a pig in order to collect its semen for breeding purposes.
The 10-minute TV scene prompted complaints from disgusted viewers and animal rights activists.
Loos said afterwards: "My arms are aching! It lasts for about 10 minutes and he starts thrusting really hard and then I grip!"
A spokesperson for Channel 5 said: "It is just a part of normal farm life."
Skeletons in the closet
Morgan had been editor of The News Of The World, but was editing The Daily Mirror when Loos sold her story alleging her affair with Beckham.
Morgan revealed in his tabloid memoir The Insider: "Two days into the David Beckham/Rebecca Loos scandal, I discovered she was my second cousin. And I had even apparently danced with her at a family wedding in Madrid. It really does come to something when your own family flog their kiss-and-tells to a rival paper."
Looking for love
In 2005 Loos took part in ITV reality show Celebrity Love Island.
The predecessor to Love Island ran for two series and featured TV, music and tabloid stars living on a paradise island and taking part in dating activities in a bid to become the winning couple.
Loos was coupled up with Olympic sprinter Du'aine Ladejo and they spent the majority of the series together. But she was voted out in fifth place and the series was won by TV presenter Jayne Middlemiss and former Westlife bodyguard Fran Cosgrove .
More reality TV
Loos was not disheartened and continues to sign up to more reality series.
These included The X Factor: Battle of the Stars in 2006, on which she performed a duet of Baby, It's Cold Outside with James Hewitt - famous for his claims he had an affair with Princess Diana.
Judge Sharon Osbourne slated their performance and told Loos, "Keep you knickers on next time".
Loos, who is openly bisexual, also took part in US show Power Lesbian UK, in protest at America's same-sex marriage laws, the Spanish version of Survivor and Sky TV's Cirque de Celebrite.
In 2008 Loos took part in the Dutch version of the reality show 71 Degrees North, in which celebrities battle across ice and snow to reach the 71st parallel north on the Norwegian North Cape.
Through the show she met her husband, Norwegian doctor Sven Christjar Skaiaa.
They now live in Norway with their two sons, and Loos works as a yoga and meditation teacher.
It seems after a colourful career in the spotlight, she may have now found inner peace.
Read more: The Beckhams
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