Kim Kardashian is not be trifled with and no one knows that better than long time BFF Jonathan Cheban as their friendship is in jeopardy when the latter signed a contract for Celebrity Big Brother UK edition.

The new mother is reportedly finally giving ultimatums to her BFF warning him to keep his mouth shut and not talk about her or her family on the new reality TV show.

According to Hollywood Gossip, the person who was introduced as Kim's best friend in the "Keeping Up With The Kardashians" series, is about to find out how Kim's ultimatum could affect his career. Cheban is a publicist who got slightly famous as Kim and her family rose to stardom. Their friendship is now tested because reports have claimed Kim is against Jonathan's participation in the Celebrity Big Brother UK edition.

Radar Online has reported that Kim is lashing out on Jonathan and even threatened to ban him on any future KUWTK episodes if he so opens his mouth to talk about her personal life. The report stated that Kim is afraid Jonathan will spill all her secrets on TV.

"She gave him an ultimatum, telling him that she didn't want him to do the show and if he did, she would stop talking to him. Kim is growing increasingly protective of her personal life and she is worried that all Jonathan is going to do is talk about her while he's filming. She told him he had better not spend the whole time talking about her," said the source.

The Inquistr reports that their friendship has been marred by distrust before as Kourtney Kardashian, Kim's older sister, accused Jonathan to spilling family secrets to the tabloids, to which Jonathan vehemently denies.

Several past KUWTK episodes revealed the closeness of the two when Jonathan helped Kim transport her first engagement ring from estranged former husband Kris Humphries and helped her steal Kourtney's breast milk to treat her psoriasis.