Joan Rivers and Kathy Griffin
08/03/2009 at 03:00 PM EDT
Joan Rivers may have built her career around her sense of humor, but the comedian has some choice words for good pal Kathy Griffin, who emceed her upcoming Comedy Central roast.
"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."