Kyle Richards is still at odds with her two older sisters, Kim Richards and Kathy Hilton. During tonight's third installment of the "Real Housewives of Beverly Hills" season eight reunion special, Richards will be seen opening up about the longstanding tension between herself and her sisters and revealing why she and Hilton have been at odds for so many years.

“I think it started with my husband [Mauricio Umansky] leaving their real estate company and opening [competitor] The Agency,” Richards tells host Andy Cohen in a sneak peek shared by People magazine on May 8.

As fans may recall, Umansky previously worked with Hilton's husband, Rick Hilton, at Hilton and Hyland.

Kyle Richards' new show has added to the tension between her and Kathy

While chatting with Cohen, Richards admitted that she and Hilton haven't spoken for about six months and confirmed that their latest dispute was in regard to Richards' new series, "American Woman," which is set to premiere on the Paramount Network in June. Kyle Richards then explained that while she and Hilton are currently at odds over her decision to create a show based on their childhood, their feud has been going on for the past several years.

Fans will recall hearing about Richards' family feud during past seasons of the show and may also recall Richards and her sister Kim fighting with one another over their late mother's Palm Springs home, which Richards and her husband reportedly bought.

Mauricio Umansky left Hilton and Hyland in 2011

In 2011, during an episode of "The Real Housewives of Beverly Hills," Mauricio Umansky revealed to his wife Kyle Richards that he had been approached to create a new real estate company based out of Los Angeles, which would be in direct competition with her brother-in-law's firm.

"It's so difficult for me to deal with that because of the family," he said at the time.

In addition to his recurring role alongside Richards on "The Real Housewives of Beverly Hills," Richards has also been seen in a number of episodes of "Million Dollar Listing: Los Angeles," which also airs on Bravo TV. James Harris and David Parnes, who are both featured in full-time roles on the show, work at The Agency alongside Umansky.

To hear more about Kyle Richards and her strained relationships with Kim Richards and Kathy Hilton, tune into tonight's episode of "The Real Housewives of Beverly Hills" season eight reunion special at 9 p.m. on Bravo TV.