After Jessie, James and Meowth interupted Katrina's battle with Ash a movie director called Cleavon Schpielbunk wanted her Raichu and Ash's Pikachu to audition for his movie.
Raichu made it through the iniial dancing round but after Raichu saw how Wigglytuff treated it co-stars, Raichu decided to walk off the stage leaving Psyduck to get the starring role.