She-Ra: Princess of Power (1985)

S1E41 Glimmer's Story

Prince Aldric of the Vale arrives in Etheria on a diplomatic mission, his charm immediately winning over the locals. Hordak, threatened by the prince's popularity and the potential alliance it could forge, dispatches the shape-shifting spy False-Face. Disguised as the prince, False-Face wreaks havoc across the kingdom, tarnishing Aldric's reputation and sowing chaos. The real prince must prove his innocence while Adora and the Rebellion race to unmask the impostor before Hordak's scheme destroys any hope of peace.