The BBC Radio 1 DJ has been cast as villain King Herod in the revival of the musical, but his recent weight loss may lead him to require extra padding for the role.
Lord Andrew Lloyd Webber is quoted as telling The Sun: "The thing is we signed Chris and now he's gone and lost all that weight. I think we are going to have to get him a fat suit.
"Herod was a big man. So it looks like it will be a fat suit."
Amanda Holden will host ITV1's Superstar, which aims to search for a lead in the upcoming revival.
She added: "Chris has lost shedloads of weight. If they stick him in a fat suit then he'll lose loads more weight, because he'll be sweating like mad in one of those."
On Moyles's casting, Lloyd Webber added: "Having Chris was my idea. I knew he could sing - I'd seen him on Celebrity X Factor and we did the usual sing-song around the piano before I hired him."
Mel C and Tim Minchin will also be among the cast of the new production, which will premiere on September 21.
Dawn French and Jason Donovan will join Lord Lloyd Webber when Superstar launches on Saturday, July 7 at 7.25pm on ITV1.
Watch a trailer for Superstar below: