If you've never heard of lavish musicals like "The Bathrooms Are Coming" or "Diesel Dazzle," you're not alone.  Yet these elaborate productions have borrowed the talents of some of Broadway's biggest names.

Tony-winning director Susan Stroman admits she "cut her teeth" on what was known as the industrial musical, extravagant productions the general public never got to see.  Instead, they were meant for corporations to show to clients, dealers, and investors.

Now, a new documentary called "Bathtubs Over Broadway" gives audiences a glimpse into this secret world.

Stroman, along with the film's writer, director, and some actors walked the red carpet for the world premiere at the Tribeca Film Festival Saturday (21 APRIL 2018) in New York."A lot of corporations would hire us to sing and to dance about their product.  And in fact, that's how I really got started choreographing and directing - I started to do industrial shows," Stroman said.Broadway legends Bob Fosse, Chita Rivera and Sheldon Harnick also loaned their talents to industrial shows before making it big.  Kander and Ebb wrote a musical for General Electric called "Go Fly a Kite" before tackling shows like "Chicago" and "Cabaret."

The idea for "Bathtubs Over Broadway" was the brainchild of former "Late Show with David Letterman" writer Steve Young, who began collecting souvenir recordings after he learned about these productions.  It was directed by Dava Whisenant.

"It follows Steve on a journey where he meets all the people that made these corporate musicals that no one had ever heard of.  It was a secret world," Whisenant said.Young says he was happy to "drag these shows from the abyss" to let people know about these amazing productions.

"It's going to be a taste of a hidden art form that was a huge part of American entertainment and culture that the public was completely unaware of because it was private, behind closed doors for company meetings," Young said.

Stroman, the five-time Tony-winning director and choreographer of such shows as "The Producers," "Crazy For You," and "Show Boat" feels these shows were "a stepping stone for where I needed to be."

"They could be very silly.  But in fact they were the way we made a living waiting for our Broadway show, or waiting for our off-Broadway show.  You know, just waiting for our one big break.  The industrial shows kept us alive," Stroman said.

Stroman laughed at some of the silly ideas.

"I did an industrial show for Miller Beer, and you know, where I had big girls dressed in beer bottles dancing around the set.  Or, you know, we did some for Honeywell Computers where we did a takeoff on 'How to Succeed in Business,'" Stroman said.

Back in the day, Coca Cola, Ford Tractors, Xerox, and others financed these productions.  But unless you were at a sales meeting for American Standard dealers in 1969, you would not have seen "The Bathrooms Are Coming."  The same is true for the 1966 General Motors musical "Diesel Dazzle," or a young Martin Short plugging new cars from Chrysler Plymouth. But now you can at least look back at the era with "Bathtubs Over Broadway."The film does not have a release date, though it's scheduled to appear in some upcoming film festivals.