Apparently, he found her books deliciously rude.
"I said that I hated the idea of my mother reading the rude bits, and suggested he must feel the same, since his books are far sexier than mine," Enright said.
Happily for Diaz, his Dominican mother doesn't read English.
And the rest of Enright's countrymen? Surely they're avid readers of her work.
"Oh, it's a conspiracy of silence," she said yesterday. "Everyone knows that I've written books. Some even own copies of them. But they would never actually discuss the contents. It's a question of privacy, you see."
What about Enright's novel The Gathering, the scabrous instant classic that won her last year's Man Booker Prize? Weren't its swipes at Catholicism a bit, well, blasphemous?
"I've never done blasphemy, ever! And I know blasphemy - my mother's a Catholic, for goodness sake! There's one borderline remark in my entire oeuvre."
It turns out that Enright's mother gave her an early lesson in religious tolerance.