The moment The Super Mario Bros. Movie landed Jack Black to play the voice of Bowser, directors Aaron Horvath and Michael Jelenic knew what they had to do.
“As soon as we cast Jack, our greatest desire was to get him to sing in the movie,” Horvath told GameSpot.
And that they did. Several times during the course of The Super Mario Bros. Movie, Bowser breaks out into song in order to wax poetic about Princess Peach, who he wants to marry. And while the song very much has a distinctive Jack Black flavor to it, it didn’t take long to get there. In fact, Horvath and Jelenic say the whole thing was a bit of a whirlwind, going from conception to more or less its final form in just a few days. Though even in that short span it evolved in a big way.