It doesn't take long for the claws to come out on this Sunday's season premiere of Bravo's The Real Housewives of Orange County.

Round one?  Gretchen Rossi vs. Tamra Barney. Picking up their feud from seasons past (Barney insinuated Rossi cheated on her cancer-stricken fiance when he was still alive), the girls go at it during a backyard get together. (Watch a clip above)

"I was pretty damn nice to her and stood there while she called me a bitch at my boyfriend's house," gripes Barney on the debut. "But...Let me give her the benefit of the doubt."

Confronted about making the slur, Rossi retorts, "Yeah. I don't think I can hold back on that. I think I was calling you and evil bitch."

"I was more than shocked," says Barney. "I really thought we had buried the hatchet."

The Real Housewives of Orange Country premieres March 6 at 10 p.m. (EST) on Bravo.

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