Joan Rivers and Kathy Griffin
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"She can [expletive] drop dead now, I'm so angry," Rivers tells PEOPLE, laughing. "She was evil. We made a pact. No matter what we say on camera ... we stay friends forever. And she really lets me have it."
When it comes to the show – which airs Aug. 9 at 10 p.m. ET – Rivers promises plenty of sharp words and big laughs.
"I was in shock at what they said," she says. "They called me evil, mean and [a] plastic surgery whore and disgusting. I kept saying to myself, 'How do they know so much about me?' "
Apart from the Comedy Central show, the comedian has plenty to keep her busy, including a regular stand-up gig at New York's West Bank Café and a residency at Las Vegas's Venetian Resort Hotel and Casino. She also will star in a new TV Land show, How'd You Get So Rich?, which begins Aug. 5 (10 p.m., ET), in which Rivers travels cross-country asking people, well, how they earned their vast fortunes.
"We go and ring doorbells and stop cars – things everybody's always wanted to do," she says. "When you see a big car on the street, you want to know, 'How did they get so rich?' So, I ask them."
Never one to shy away from going there, Rivers says she loves her new gig. "I swear I'm a peeping tom with liver spots," she says. "I have no problems [asking people]."
"And they tell you," she says. "The people we dealt with all made it themselves in this economy, so it's a very aspirational thing."
