Exact details of his new musical - which he first spoke about in February at the WhatsOnStage Awards - are shrouded in secrecy, but he revealed some telling teasers in a recent interview in Australia.
Speaking to Sydney Sunday Telegraph's Jo Litson ahead of his appearance in Sydney Theatre Company's revival of Tom Stoppard's Rosencrantz and Guildenstern are Dead, Minchin said: "[the new show] is still embargoed even though I've been working on it for six months.
"But it's a very interesting, arty but much-loved early ‘90s film we are adapting for the stage: very conceptual, somewhat Stoppardian. It will be more complex and dark [than Matilda]."
He also revealed his is reuniting with Matilda director Matthew Warchus, saying the two "are going to try and start it quietly". Good luck with that, guys!
Click here to read the full interview