Williams, 36, and wife Ayda attended the preview night of the new show at the Opera House in Manchester to support Williams' best pal Jonathan Wilkes, who is appearing in it.
The show is for adults and tells the tongue-in-cheek story of Evil King Foo who kidnaps Princess Crystal and some of Panto's most popular characters start to strike in protest.
The show is running at the theatre until November 27 and also stars Paddy McGuinness, who, along with Wilkes tries to save the day and restore order to the Panto world.