Don’t make Joan Rivers angry. You probably already knew that, but CNN anchor Fredricka Whitfield seemed unaware when she interviewed the veteran comedienne earlier this week.

Joan RiversJoan appeared on CNN earlier this week

In the interview, which aired on Saturday, Rivers' stormed out after objecting to Whitfield’s 'negative' line of questioning, which primarily focused on her often controversial comedic style.

Referring to River’s E! 'Fashion Police' series, which see her critiquing celebrities outfits, Whitfield said it was, “very mean in some ways.” But Rivers quickly cut her off saying, “It’s not mean, it’s not mean, it’s not mean I tell the truth.”

More: Joan Rivers Heckled By Anti-fur Activists At Book Event

Rivers then went on to say, “I’m sure I say the same things that all your viewers say to their friends sitting next to them on the couch.” Adding, “We’re one of the few shows that says ‘that’s an ugly dress.’ … These ladies make $28 million a picture. You really think that Nicki Minaj cares I didn’t like her dress?”

Joan Rivers and Kelly OsbourneJoan hosts E!'s 'Fashion Police' alongside Kelly Osbourne

But Whitfield didn't seem to catch on that Rivers' was genuinely annoyed by her line of questioning and continued to press the comedienne, moving on to ask her if she ever felt there were boundaries when it came to her style of humour. Rivers responded by saying “Life is very tough, and if you can make a joke to make something easier and funny, do it. Done.”

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Things then got more heated when Whitfield asked Joan about her decision to wear fur on the cover of her latest book, Diary of A Mad Diva. "You know, this whole interview is becoming a defensive interview," Rivers said. "Are you wearing leather shoes? Then shut up.”

It was the final straw for Rivers, who ended by saying she'd been “making people laugh for 50 years”. She then walked out of the studio after telling Whitfield she was “not the person to interview someone who does humour.” A stunned Whitfield simply responded with, “are we serious?”

Joan RiversJoan Rivers' Diary of a Mad Diva is out now

Rivers did not return to the interview and Whitfield later said the comedienne had “kept her microphone on and she continued to talk and drop some very unflattering four letter words. So, yes, she was serious.”

Joan Rivers' Diary of a Mad Diva is available in bookstores now.