Harry Potter spinoff "Fantastic Beasts and Where To Find Them" has not even been released yet and the author is finished with the second part.
"We've done the first one, she's written the second one, she's got ideas for the third one," he said.
"Fantastic Beasts" is an upcoming 2016 British-American fantasy drama film written by Rowling as her screenwriting debut. It is a spin-off of the Harry Potter film series, directed by David Yates.
It is scheduled to open in US theatres on November 18.