The Daily Star claims that the raunchy footage - alleged to be the second the former couple shot together - is being shopped to distributors for between £19 million ($30m) and £24m ($38m).
A source told the tabloid: "It's definitely Kim in the video. And it's even raunchier than her last one.
"There are all kinds of eye-popping moments... Kim fears this will damage her relationship with Kanye West."
However, a spokesperson for Kardashian has since told Gossip Cop: "This story couldn't be further from the truth. This tape doesn't exist."
Meanwhile, Kim has shot down rumours suggesting that current beau Yeezy was planning to ask her to marry him on her birthday, insisting that Keeping Up With The Kardashians executive producer Ryan Seacrest started the speculation.
She told E! Online: "I don't know where Ryan came up with that. Ryan, I'm so mad at you, where did you come up with that? You're starting rumour.
Kimmy added: "It's just a rumour. But I had an amazing birthday, very intimate and very special."
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