The Simpsons Movie/WMG

"President Schwarzenegger" was actually a disguised Rainier Wolfcastle
In the Simpsons universe, Arnold Schwarzenegger does end up successful enough to get elected president, but he eventually decides that he's tired of the stress of politics, and he misses his simpler days as an action star. Meanwhile, Rainier Wolfcastle decides that he's tired of being seen as a brainless action star, and wishes that people would take him seriously. One day, he meets Arnold Schwarzenegger by chance, and they both realize how much they resemble each other. Realizing that each has the life that the other wants (a carefree life as a movie star for Arnold, power and respect for Rainier) they switch places à la The Prince and the Pauper.