Mantel's literary agent, Bill Hamilton, said Tuesday the author had no comment on the controversy over her lecture. "The article speaks for itself," he said.

Mantel last year became the first woman to twice win the Man Booker Prize, for her novel "Bring Up the Bodies." She previously won in 2009 with "Wolf Hall."

Her novels focus on the Tudors -- and in the lecture, she draws a parallel between the current fascination with Catherine's body and the public scrutiny under which the wives of Henry VIII sought to produce a male heir.

Last week, an Italian magazine provoked an uproar in the UK media when it published pictures of a bikini-clad Catherine on vacation, with her "baby bump" visible. Palace officials said they were disappointed by what they said was a clear breach of privacy.

"Long before Kate's big news was announced, the tabloids wanted to look inside her to see if she was pregnant," Mantel said.

"Cheerful curiosity can easily become cruelty. It can easily become fatal. We don't cut off the heads of royal ladies these days, but we do sacrifice them, and we did memorably drive one to destruction a scant generation ago."

The institution of monarchy may be irrational, Mantel added, but those outside don't have to forget their principles as they observe the "entertainment" the royals provide.

"I'm not asking for censorship. I'm not asking for pious humbug and smarmy reverence. I'm asking us to back off and not be brutes," she said.

Emily Bell, director of the Tow Center for Digital Journalism at the Columbia Journalism School, defended Mantel via Twitter, saying the furor exemplified the author's point about the media's role.

"The Middleton row is caused by the Mail turning Hilary Mantel's rather wonderful lecture into an example of exactly what Mantel warns of..." she said.