Lisa Vanderpump and Kyle Richards butted heads during filming on The Real Housewives of Beverly Hills season six.

In a sneak peek from tonight's new episode of the Bravo reality series, the two women are seen sitting with their co-stars when things turn ugly. According to the preview, Richards brings up an issue that took place in 2012, in which she reportedly owned up to saying Vanderpump had a big ego, and claimed Vanderpump should also own up to something she apparently said.

"I will not f---ing tell a lie. And you know what, to me our friendship is too important," Richards said, via PEOPLE Magazine on Monday, of her reasoning behind her 2012 comments.

As the clip continues, Richards urges Vanderpump to tell "the truth," but doesn't say what it is that she's hinting at. Then, Lisa Rinna is seen claiming that both Vanderpump and Yolanda Foster are to blame for whatever it is that is coming between Vanderpump and Richards.

"I see it so clearly. We are collateral damage in the game of Lisa Vanderpump and Yolanda. Two highly narcissistic individuals who are battling it out to be the queen," Rinna said.

In her blog last week, Vanderpump addressed comments recently made by Rinna, which suggested she and Richards had played a bigger part in the Munchausen syndrome conversation than what fans saw online.

"We never supported the theory of Munchausen's, because although her actions were strange--her constant sick selfies and endless treatments--she had been diagnosed with Lyme disease. I believed Munchausen to be when you manufacture an illness," Vanderpump wrote to fans.

"Kyle and I discussed what had transpired, as we were still aghast at LR's statement regarding Munchausen. I then told Kyle I THOUGHT LR was going to drag her into it...and told her as much. I would not have told Kyle that if I had just suggested to LR to include her," Vanderpump concluded.

For more Lisa Vanderpump, tune into The Real Housewives of Beverly Hills season six, airing on Tuesday nights at 9 p.m. on Bravo, and check out a sneak peek at tonight's new episode below.