Another possible cause of the terrible split between the two socialites has just shown up: it seems that Nicole saw the infamous Paris Hilton sextape and that made her friend angry and bitter ever since.

Nicole Richie denies watching former best friend Paris Hilton's sex tape and says she would not do things that would 'gross' her out.

Rumor has it: "One Night In Paris," the dirty home-made Paris Hilton and Rick Salomon sex movie was shown by Nicole Richie to friends at a party.

Nicole Richie strongly denies any involvement in the public viewing of the tape and has explained her point of view: "A, I don't watch porn, and B, I don't want to see someone I've known forever having sex. I mean, that's gross!"

Paris' ex-boyfriend, Rick Solomon released the tape that shows the music star wannabe Paris Hilton while involved in a number of sex acts, including full penetrative sex and oral, and also performing a racy striptease.

Last week Nicole said that she and Hilton heiress have split due to her sudden change of lifestyle. On the other hand, the Hilton side declares they split because Nicole was too jealous on her fame, success and good looks.