Credit: Courtesy of PETA

Bethenny Frankel is no shrinking violet. The pregnant Real Housewives of New York star posed nude for a PETA billboard that was unveiled Dec. 15 in Manhattan's Times Square. Now, she's talking back to the housewives and other haters who have suggested that the butt-baring photo was heavily airbrushed -- and she's shared the photo evidence (the original, untouched image) exclusively with

"Everything I'm about is being honest and being upfront," Frankel, 39, tells "So if people are talking and saying [the photo] was airbrushed...then, you know what? Here's the picture. Have it your way."

The author of new cookbook The Skinnygirl Dish adds that she would "never, ever allow them to put up a billboard that was really far from the truth."

Now four months pregnant with her first child, Frankel disrobed for the shots on a Manhattan rooftop in September. Although she's never posed nude before, she says "I wasn't that freaked out about it. I don't know why. PETA has no interest in making me look sleazy. It was such an honor."

As for the pregnancy? "It's been great. I haven't been particularly nauseous, and I get a decent night's sleep, which is refreshing. My boobs are big, but other than that, nothing's crazy."

Still, she confides that expecting a baby is a "weird" experience, "To be honest, being pregnant is weird. Whoever says any different is probably lying. It's a strange, strange thing."

The dad-to-be is Frankel's fiance, Jason Hoppy. Although the couple announced their engagement in October, they have put off planning their nuptials until after Frankel gets through her pregnancy, a book tour, the third season of Housewives (which just wrapped shooting) and her new untitled solo reality show. "There's no plan whatsoever!" Frankel says.