Instead, as the audience rose to their feet in acclamation on the first night, the TV talent judge strode on to the stage with the air of a man crowning the 2018 winners and congratulated everyone involved, not least the youngsters in the lead roles.
Chichester has a long tradition of nurturing the actors of tomorrow through its Youth Theatre under Director Dale Rooks but this production is her first family show to be produced during the main Festival season.
It was also a world premiere adaptation by Bryony Lavery of Walliams’ best-selling book.
Walliams is every bit a modern Roald Dahl - with adults often delinquently evil and children as brave and imaginative as they are vulnerable. Packed with the enduring body-parts humour that kids love and topped off with some sugary-sweet morality.
The Midnight Gang gives the account of five sick children in the Lord Funt Hospital who relieve their boredom by exploring the building in the night and making their dreams come true.
It’s a pursuit that is fraught with difficulty. As George (Rafi Essex) sets out to fly aided by a bunch of helium-filled balloons, it’s an elderly lady who ends up crashing through the glass roof into the night sky.
The young stars are pretty much faultless, singing and joking their way through Joe Stilgoe’s music and lyrics.
The stars on the first night were the excellent Tom (Cody Molko), Amber (Jasmine Sakyiama), Robin (Felix Warren), Sally (Cerys Hill) - and of course George. They will alternate their roles with five other young actors during the run.
But for Walliams there was a sense of coming full circle too. As he told the audience, as a teenager he regularly came to the Chichester Festival Theatre and it was those visits that inspired his comedy and all that has followed since.
So there was real pathos, not just for Sally fighting for her existence in the fictional plot, but for Walliams seeing his work unveiled on a stage that first gave it the seed of life.