The Britain's Got Talent judge is set to appear on stage
Comedian Richard Blackwood will join her as Donkey, but Shrek is yet to be cast.
It’s not the first time Amanda, 39, has appeared in a musical.
In 2003 she played the lead in Thoroughly Modern Millie and was nominated for a Laurence Olivier Award for Best Actress In A Musical.
Shrek The Musical will open in London’s Theatre Royal next May.
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