One of Robin Williams' final unseen films may never be released.

In Boulevard, which premiered at New York's Tribeca Film Festival, Williams plays Nolan Mack, a married man who is forced to confront his sexuality after he falls in love with a male prostitute.

Boulevard is a beautiful, sad movie about a guy who falls in love with a gay prostitute, basically comes out,” Williams said just weeks before he took his own life. “He's married, and he has to come out to his wife. It was powerful to do.”

An unnamed source told The Mirror that film may never be released.

“It's really sad but it is looking impossible that Boulevard will ever see the light of day now. … [F]or many reasons, it is looking very unlikely.”

“There is one suggestion it isn't up to scratch and is failing on merit to find anyone to distribute it,” the source said.

A Merry Friggin' Christmas, the first of Williams' four unseen films arrives in theaters on November 7, while Night at the Museum: Secret of the Tomb opens in December. Williams also plays the voice of Simon Pegg's dog in next year's British comedy Absolutely Anything.