Isla Fisher has admitted she was "really shocked" to learn of Nicole Kidman's divorce.

The Oscar winner confessed she had not predicted her fellow Australian's marriage breakdown.

"I'm really, really, really shocked," Isla, 49, told comedians David Spade and Dana Carvey on their Fly on the Wall podcast, before explaining she had not actually spoken with Nicole since the news broke on 30 September.

"I have left a message. I have not connected yet."

However, she added, she preferred not to speak about the split, given that Nicole, 58, and her estranged husband, Keith Urban, 57, share daughters Sunday Rose, 17, and Faith Margaret, 14.

"I don't really wanna comment on that because there are children involved," she said. "Tough times to be in the public eye."

Elsewhere, Isla reflected on having penned Young Adult novels with her mother when she was still a teenager.

Titled Seduced by Fame and Bewitched, the books included "racy" scenes that Isla admitted she had felt ill-equipped, at the time, to write.

"It had sex scenes in it, and I was only 18," Isla recalled. "And so I hadn't even had a boyfriend at that point, so it was quite awkward with my mum, pitching quite racy things!"