The 31-year-old author, who is releasing his new children's story and first novel today, said the talks are already on to turn the tale into an animated musical movie, reported Female First.
Michael Gracey is on board to direct the project and Fletcher said he was "really lucky" to have him on board.
"I couldn't believe that, it's so cool. Michael was meant to be here today but everything has gone rapidly for him so he couldn't be, but it's okay...
"If you have to be somewhere else than filming with Hugh Jackman and Zac Efron is a good excuse. He's an incredible director, so we are really lucky to have him on board," he said.