When Joan Rivers visited the 'Howard Stern Show' on Tuesday, March 25, she had some choice words to say about Lena Dunham and her weight. So choice, in fact, that the raunchy host himself actually vehemently disagreed with the outspoken, 80-year-old 'Fashion Police' star. 

"Lena Dunham, who I think is again terrific, how can she wear dresses above the knee?" Rivers questioned Stern about the 'Girls' creator's fashion decisions. (Ooh, dresses above the knee -- so scandalous!)

"I think the thing we love about her is that she doesn't give a s---," Stern retorted, defending Dunham. (Not too long ago, the radio host famously apologized to the actress after his own series of jabs about her weight.)

“But that’s wrong!" Rivers cried. "You’re sending a message out to people saying, ‘It’s OK! Stay fat! Get diabetes. Everybody die. Lose your fingers.'"

"I don't think she's sending a message out to anyone saying anything other than, 'I'm going to make you laugh,'" Stern countered.

When Rivers suggested that she would like to reach out to Dunham to show her how to dress, she was well aware of what the actress' reaction would be: "'F--- off!'"

"That's your thing. My thing is, 'Hey. I'm free. I don't sit and think about what you think or what anyone else thinks,'" Stern imagined how Dunham would respond to Rivers' request, even fitting in a little dig at the comedienne's fondness for going under the knife. "She would say to you, 'Listen Joan, I'm not going to be the type of woman that needs to do the Botox and face lifts and all that stuff because I'm going to live my life the way I am.'"

But Rivers (surprise, surprise) continued to argue, dispensing endless backhanded compliments to Dunham.

"I love, love, love that she's funny, I love that she did well...but don't let them laugh at you physically," Rivers argued.

An argument Stern counters with the double-standard: Men can do physical comedy, but women can't?

Ultimately, Rivers had this to say:

"If you look the way you look, Lena, and that's fine and you're funny, don't say it's OK that other girls can look like this."

"Try to look better," she concluded.

Listen to the blood-boiling interview below.

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