"To quote Bethenny: 'I just threw up a little in my mouth,'" wrote Giudice in a Tuesday post on her Twitter account.
Frankel -- who confirmed she was "less than two months pregnant" in Ocotober -- toldThe New York Post in a Tuesday report that she is proud of the PETA ad because "it's so tasteful and beautifully done."
"I am especially pleased because it doesn't look like there's been any airbrushing, and I was already pregnant when I shot it," she told The Post.
"I am excited to know that I'll be there on a billboard while everybody is doing their Christmas shopping and celebrating the new year."
Giudice begs to differ with Frankel's timeline and wonders how pregnant she really could have been during the shoot.
"Help me understand this," posted Giudice to her Twitter account.
"Bethenny is happy with her naked pic because she was 'already pregnant' at the time. She says she's now three months along, but she did the shot in August. Even if she's four months pregnant now, she would've been, like, one hour pregnant in the pic."
In addition, Giudice posted that "someone should tell Bethenny that sperm does not make you look fat."
"I'm not buying the airbrushing thing in any case," she added.
While some might consider the fact that Giudice appears onThe Real Housewives of New Jersey and Frankel appears on The Real Housewives of New York City as enough of the reason for less-than-cordial relationship, Giudice claims it stems from a September TV Guide interview in which Frankel said Giudice is her "least favorite housewife" because she is "whiny and unintelligent."
"It's cool if you like Bethenny. She probably didn't give an interview to TV Guide that hated on you. Me, not so lucky," posted Giudice to her Twitter account.