She may be nearly 40, but Nicole Kidman would be Hugh Hefner's top pick of Australians to feature in international men's mag Playboy.

And what of Australia's own Princess Mary?

Hefner's deemed her "too ladylike" for the magazine he founded in a candid interview with New Idea magazine.

"She looks like a nice woman, but this outfit isn't sexy at all," Hefner said, referring to a recent photo of Princess Mary.

Kidman, on the other hand, is "bewitching".

"She's bewitching, and the vision of her with a cigarette in one hand and her knickers in the other as a delicious French au pair will haunt my fantasies for months," said Hefner, who had saw Kidman perform on stage in The Blue Room.

"I better add, she's a terrific actress."

In New Idea, which hits stores on Monday, Hefner says model Elle McPherson, singer Kylie Minogue and actor Naomi Watts would all be welcome to pose for Playboy.(AAP)