(Cover) - EN Showbiz - Paris Hilton is reportedly envious of how successful Kim Kardashian has become.

The pair used to be close friends and even shared the fact that they appeared in their own sex tapes.

RadarOnline reports that despite the pair speaking during Diddy's party in Cannes last week after years of estrangement, the original socialite is still holding a grudge.

"Kim will always be a sore spot for Paris because she believes that without her Kim wouldn't have the success she has in her life," a source told the site.

"Paris thinks Kim wasn't a loyal friend to her and only used her to gain fame and that she is ungrateful for everything Paris claimed to do for her.

"Paris is extremely jealous of Kim's success with her reality shows as Paris' last foray in television was a complete flop.

"Adding to Paris' angst is the attention that Kim is getting from dating Kanye West. Paris has been dating DJ Afrojack, but he's nowhere near the fame league that Kanye is, and adding to that, the relationship is cooled."

Paris has also been very publicly upset when asked in interviews about her not being as famous as Kim now although she does have very successful fragrance and product lines. (C) Cover Media