Is Kathy Hilton really joining the sixth season of The Real Housewives of Beverly Hills?

Kim Richards MIA During Nicky Hilton's Bridal Shower

Last week, a report claimed Hilton would be a part of the upcoming season of the Bravo reality series -- and that Kim and Kyle Richards were in the dark about it. A short time later, the rumor appeared true, when Hilton told fans she couldn't get in touch with her younger step-sister.

Kim Richards Celebrates Brooke Brinson's Bridal Shower

According to a Radar Online report on Friday, Hilton had been brought aboard The Real Housewives of Beverly Hills without her sisters knowing, and was instructed to keep them in the dark.

“They’ve wanted to switch things up by trading the sisters for their much more famous sister,” a source close to the show told Radar. “The one rub is they told Kathy not to say anything to them. So her sisters, like the rest of the cast, are in the dark about the new casting.”

The site claimed producers of the show have been eying Hilton from the start.

“Execs initially wanted Kathy for the show years ago, but she passed. And she ended up recommending her sisters who were clamoring to do it,” the source said.

Despite her initial tweet, Hilton later denied she was a part of the show on Twitter.

 For more Kathy Hilton, check out the video below, which featured Bethenny Frankel revealing a fun fact about her.

Tags: kathy hilton kyle richards Bravo The Real Housewives of Beverly Hills Reality TV