Actors picking parts

A director is screen testing Sylvestor Stallone and Arnold Schwarzenegger for a new film about classic composers. Not having figured out who to give which part to, he asks Sly who he would like to be.

Stallone says I like Mozart. I want to be Mozart

So the Director says, Very well, you can be Mozart Then he turns to Arnie and says Arnie, who would you like to play ?

And Arnie says Ah'll be Bach!