The Prince and the Pauper (1978)

Tom Canty, the youngest child of a very poor family living in Offal Court in London, sees one day Edward Tudor, the Prince of Wales. Coming too close in his intense excitement, he is caught and nearly beaten by the royal guards. However, Edward stops them and invites Tom into his palace chamber. There, the two boys get to know one another and are fascinated by each other's lives. They have an uncanny resemblance to each other, so they decide to swap clothes "temporarily". But things turn out differently.