Davies had to ditch his idea of writing the Harry Potter creator into this year's Christmas Day episode as a gift to young fans, after Tennant declared he thought the idea sounded like a spoof. Had the show been allowed to go on, the episode would have featured Rowling's imagination, a world full of magic and wizards, which turns into reality after she is attacked by a giant space bug.
"Zap! JK's imagination becomes real! A world of Victorian magic replaces the present-day world," the Sun quoted Davies explaining. "The Doctor arrives and has to battle through a world of witches and wizards, with wands and spells, to reach JK Rowling at the heart of it all," he said.
But when it was known that tenth Time Lord Tennant was not in favour of the idea, Davies emailed his bosses about it. "David doesn't like the JK idea. He thinks it sounds like a spoof so we've paused slightly, wondering whether to win him round or just abandon something he"s not going to be happy with," he had written.
A very unhappy Davies had to do away with the idea, revealing to his colleagues that Tennant's happiness comes first. "We've got to keep him happy. He keeps us happy. Plus he might be right. So that idea has parked itself," he added.