Joan Rivers knows how to dish it out, but she can become defensive when criticism is leveled at her. The plastic surgery-addicted comedienne walked out during an interview last week when CNN interviewer Fredericka Whitfield pressed her about the perceived meanness of her comments leveled on celebrities’ sartorial choices on “Fashion Police,” her show on the E! network.

“It’s not mean, it’s not mean, it’s not mean, I tell the truth,” Rivers, 81, insisted.

Known for her caustic and politically incorrect humor, Rivers defended her comedic style by saying that humor helps people get through rough times.

“Life is very tough and if you can tell a joke to make something easier and fun then do it. Done.” (Rivers has spoken about her own drive to get back to working in comedy immediately after the 1987 suicide of her husband, Edgar Rosenberg.

In addition, Rivers assured Whitfield that the celebrities she pokes fun at are not fazed by her red-carpet fashion critiques.

The interview really went south when Whitfield began questioning Rivers the photo of her wearing fur on the cover of her new book, “Diary of a Mad Diva.”

After accusing the interviewer of hypocrisy (“Are you wearing leather shoes? Then shut up”), Rivers ripped out her earpiece and stormed off camera.

“All you have done is [be] negative. I’ve made people laugh for 50 years, I was put on this earth to make people laugh, my book is funny, I wear fur that was killed 15 years ago, I support animal rights,” she said emotionally.

Rivers insists that her reaction to the interviewer was authentic and that her abrupt departure was not a publicity stunt.

On the other hand, David Letterman’s getting up and leaving in the middle of a conversation with Rivers a couple of days later was intentional. The late night talk show host may have been trying to give Rivers a taste of her own medicine, but she seemed to like it.

While she clearly got Letterman’s message, she used the opportunity to her advantage. The comedienne, now alone on stage, proceeded to interview herself and crack some off-color jokes about a certain part of her anatomy.

There really doesn’t seem to be much that Rivers can’t laugh off…except for an interview with someone who is “not the one to interview a person who does humor,” as she called Whitfield.