The husband of Australian children's author Mem Fox was Friday convicted of having sex with an underage male student.
Fox, the author of a host of popular children's books including the internationally acclaimed Possum Magic and Wombat Divine, gaped and declared it "absolutely unbelievable" as her husband was found guilty.
Malcolm Fox, 67, had pleaded not guilty in the Adelaide District Court to four counts of unlawful sexual intercourse with the drama student, then aged 17, between June and December 1984.
It was not clear why it had taken so long for the case to come to light.
The age of consent in the state of South Australia for sex with a person in authority, such as a teacher, is 18.
The court heard the youth turned to Fox for help after he had been sexually abused by another, older man, while Fox claimed the student made "embarrassing" and unwanted advances towards him.
Judge Gordon Barrett said he found Fox's account "intrinsically implausible".
"I find it unlikely in the extreme that the complainant, who was 17 at the time and had been the accused's student for several years, would suddenly make so confronting a sexual advance," the judge said.
By contrast Barrett said the "complainant gave a credible account of sexual experiences with the accused," and he was satisfied that -- though consensual -- illegal oral sex acts had taken place, convicting Fox of the charges.
Fox was due to be sentenced in two weeks' time.