Credit: Dave M. Benett/Getty

Howard Stern isn't always the guy in the conversation to potentially offend -- Elle Macpherson was the one who made a head-scratching remark while bantering on Stern's Sirius XM radio show Tuesday.

The stunning Australian supermodel and Fashion Star mentor, 47, chatted gamely with the shock jock, 58, as she promoted her brand-new NBC style competition costarring Jessica Simpson and Nicole Richie.

The chat got racy, naturally, when Stern asked if the statuesque cover girl keeps any photographs from her legendary career on the walls of her home. Macpherson replied that one wall in her bedroom features a Herb Ritts shot taken circa 1990 -- in which she's on the beach and nude, save for "a gun holster around my waist," she explained. "I love the image," she gushed, adding that it was snapped "from behind."

Stern worried that the butt-baring shot could traumatize Macpherson's sons Arpad, 14, Aurelius, 9.

"Do your children get upset by that? It's probably upsetting that his mother's ass is in the bedroom, and if the kids bring over friend," he pointed out.

"No," Macpherson replied. "I just think youre being absolutely Jewish."

"Why is that Jewish?" a dumbdounded Stern wondered. "I've had this discussion with people who aren't Jewish."

"Because you're being overprotective," she joked of an old "Jewish mother" stereotype. "You sound like a nagging mother, 'Eleanor, should you have that picture in your room?' My children are very well-balanced."

Quipped Stern: "I once saw my mother come out of the shower, it traumatized me."

"I can imagine, if she looks like you," Macpherson replied. "Sorry, that just slipped out!"

Deadpanned Stern: "I am ready to break up with you."

Fashion Star debuts Tuesday night on NBC.