Robin Williams and Bobcat Goldwaith Unite in "World's Greatest Dad"

Robin Williams is set to play Lance Clayton in the dark comedy "World's Greatest Dad," written and directed by Bobcat Goldwaith.

The film was released to limited theaters on Aug. 21, and will expand to additional theaters by Aug. 28.

The Associated Press reports how from pre-production to the release of "World's Greatest Dad," things seem to be working in Goldwaith's favor. He originally did not expect Robin Williams to star in the movie. He merely mentioned his new project to Williams, and Williams had alternate plans after learning of the script. Williams decided to sign-on after reading it.

Goldwaith also did not expect to receive coverage from NBC's "The Tonight Show" after being banned, but that proved to be an incorrect assumption as well.

The Hollywood Reporter reports Goldwaith's reluctance to use Williams's popularity to sell the movie, and instead decided to market the movie based on the talent and potential of the screenplay.