It’s more than just on-camera catfights!

Adrienne Maloof is opening up in the new issue of Life & Style about her feud with Brandi Glanville — sharing the biggest betrayal yet: Brandi’s newfound closeness to her ex-husband, plastic surgeon Dr. Paul Nassif.

“It’s the ultimate betrayal,” Adrienne tells Life & Style, sharing her devastation when she found out this past December that Brandi had been getting close to Paul. “It’s extremely hurtful.”

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Viewers may be surprised that the two have been exchanging private text messages and public tweets after Brandi and Paul famously fought on the Dec. 10 episode — even Adrienne had to drag him away from the drama after Paul called Brandi a “b*tch” and “piece of sh*t” under his breath.

“We’re friendly,” Brandi admits to Life & Style. “Every once in a while, he’ll text me. He’s very nice.”

Adrienne, 51, and Paul, 50, were married for 10 years before their separation in July, when things quickly turned bitter with allegations of abuse being thrown around. The couple finally reached a settlement in November — and by December, Paul and Adrienne’s season-three sparring partner, Brandi, 40, were exchanging sweet tweets.

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Of the bond Paul and Brandi have formed, Adrienne doesn’t believe it's authentic. “I believe getting close to Paul is a ploy on Brandi’s part to make herself more relevant,” his former wife warns. “I feel the sudden friendship with him was thought out and vindictive.”

But Brandi defends herself, telling Life & Style: “She [Adrienne] is not a very nice person; she pretends to be. I called her to talk to her about the situation. But it’s hard for me to apologize to someone when I feel like they owe me an apology prior to that.”

TAKE OUR POLL: Are you Team Adrienne or Team Brandi?

For more on Adrienne’s exclusive interview, pick up this week’s of Life & Style, on newsstands now.