Joan Rivers has proved once again that she’s a very naughty girl as she’s let rip at Lena Dunham in her new book.

According to the New York Daily News the veteran comic who loves to mock and shock has targeted the Girls star in her latest publication, Diary of a Mad Diva, criticising her for her persistent nudity and "boastful" attitude.

Rivers calls the HBO star the "first fat girl naked on the television,” saying that television viewers watch her show with “their hands over their eyes.”

If Dunham is free enough to "have her fat ass on display," she writes, why isn't she "free enough to have a f-ing salad once in a while?"

Rivers adds that if she has to see Dunham's "ass, boobs or tattoos" again, she wants HBO charged with crimes against humanity.

She also considered Dunham "boastful" during a women's event where she claimed to be a "pioneer" for women in Hollywood while standing in front of Tina Fey and Amy Poehler.

So, no Girls’ box set for Joan Rivers then.