Insiders recalled the moment Kim Kardashian discovered her X-rated video was online in a new two-part Channel 4 documentary, subtitled Billion Dollar Dynasty.

Former couple Kim and Ray J, who got together in 2002 when both were 21, made the infamous tape during her birthday celebrations that year and it was later released in 2007.

The reality star, 42, was reportedly in tears when admitting there was a sex tape, but cynics claim she was urged to make it by Paris Hilton.

Kim Kardashian admits she did a sex tape because she felt horny

‘Kim was in tears’: Insiders recalled the moment Kim Kardashian discovered her X-rated video was online in a new two-part Channel 4 documentary, subtitled Billion Dollar Dynasty

Socialite Paris, 41, and her then-boyfriend Rick Salomon, who is 13 years her senior, starred in the tape which was leaked in 2003 and which Rick himself began to sell in 2004.

In a throwback clip which was shown in the new documentary, Kim was heard telling her sister Kourtney: ‘I did it because I was horny and I liked it’

It was revealed that Kim was at the beach in Australia with Paris when it was leaked and she was reportedly ‘in tears, in pieces but admitted there was a sexy tape’.

Sex tape: Former couple Kim and Ray J, who got together in 2002 when both were 21, made the infamous tape during her birthday celebrations that year and it was later released in 2007

In a throwback clip which was shown in the new documentary, Kim was heard telling her sister Kourtney: ‘I did it because I was horny and I liked it’

When Paris’ sex tape was released, it ‘put her on another level when it comes to stardom’ and people believe Paris led her down that path to make hers.

Kim’s ended up being the highest grossing celebrity sex tape of all time and the reason they got Keeping Up With The Kardashians recommissioned.

It was claimed that the notorious sex tape with her ex made more than a million dollars in revenue within its first six weeks of release, according to financial records.

The drama surrounded it intensified this year, when Ray J gave an exclusive interview to DailyMail.com claiming there was a second tape in existence.

Kim and Ray J previously signed an agreement with Vivid regarding their sex tape, and following the reality star’s lawsuit, she and Ray J reluctantly agreed to release it.

Heidi and Spencer Pratt recall Kim Kardashian being on The Hills

Pals: The reality star, 42, was reportedly in tears when admitting there was a sex tape, but cynics claim she was urged to make it by Paris Hilton

Before finding fame, Kim told Entrepreneur Sheeraz Hasan, who features on the show: ‘I want to be the most famous person in the world’

Speaking about how Kim and Paris’ friendship started, he explained: ‘Kim was her shadow, her intern. What Kim did was very smart at the time, she was photo bombing and taking media opportunities’

The documentary explores how the famous family has defied critics to build a brand that has earned billions, and transformed social media.

Ray J gets emotional while discussing Kim Kardashian sex tape

Using archive footage and candid insights from close friends, the documentary will explore the deals and decisions that have helped them to build a family brand and turn every potential setback into a money-making opportunity – and become hugely wealthy in the process too.

The first episode looked back to 2007, when Kim Kardashian was a relative unknown, living in LA and working as an assistant to Paris Hilton, as well as examining the beginnings of the family’s first reality TV show.

The second episode of this two-part programme will be available to stream or download on All 4, for free, following the transmission of this episode on Sunday 8th January.

Documentary: The second episode of this two-part programme will be available to stream or download on All 4, for free, following the transmission of this episode on Sunday 8th January