Kim Kardashian is still furious with Joan Rivers for calling her daughter "ugly."

The Keeping Up with the Kardashians star, who is set to wed rapper Kanye West in a $400,000 ceremony at Forte di Belvedere in Florence, Italy on May 24, and her younger sister Khloe Kardashian reportedly refused to sit beside the Fashion Police host at the NBC Upfronts event in New York City on Thursday night because they are fed up of her mocking their family on the E! series, including 11-month-old North.

"Khloe and Kim were seated next to Joan Rivers, but they had them move her. Kim and Khloe both don't want drama and can't fake it anymore with Joan, so they asked the staff to keep them separate. Apparently it was a hard task because two other people have issues with her and also asked to be seated away from her. It was a juggling act keeping Joan away from everyone!" a source said.

Joan made the remarks about baby North in January and also said the tot was "desperately" in need of a wax. Despite her issues with the comedienne, Kim, 33, has never confronted the 80-year-old star for her comments.

The insider said the duo also came face-to-face backstage at Jimmy Fallon's late night talk show recently, but the reality TV star "was polite and didn't say anything. They even took a pic together when Joan asked."

Joan has also spoofed the brunette beauty's sex tape with ex-boyfriend Ray J and made fun of her stepfather, Bruce Jenner, for his new appearance on Fashion Police in the past.