Simon Cowell's rivalry with Sir Bruce Forsyth is set to spill over into the X Factor musical.
The Sun reported that a stunt involving the pair appears in a flashback during the stage show, when a 12-year-old Simon wonders about the future of TV.
In the scene, mini-me Simon, wearing his trademark high-waisted trousers, attacks Sir Bruce with custard pies and brands him "out of date".
Noel Edmonds and Cilla Black also get hit with pie, before Bruce is hit in the scene finale.
Sir Bruce has criticised Simon's other show Britain's Got Talent for putting young acts under pressure.
But Simon hit back, saying he feels a responsibility towards the young contestants on the show and would not put them on stage if he thought they'd be miserable.
The X Factor musical, I Can't Sing!, co-written by Harry Hill, stars Nigel Harman as Simon, whose company is co-producing the show.