Most Broadway shows will offer live-streaming as a regular part of their marketing effort — or to add a valuable revenue stream — according to a veteran producer.

Ken Davenport, who recently live-streamed his “Daddy Long Legs” show across 135 countries, for free, said ticket sales and the cast album all saw an uptick in sales after the Dec. 10 stream.

In fact, 150,055 people streamed the musical — enough to fill up the 130-seat theater eight shows a week for 2.7 years.

It was the first time a Broadway or off-Broadway show was live-streamed, Davenport said.

“I’ve already been contacted to consult about [streaming] other shows,” Davenport told The Post this week. His other shows include “Kinky Boots” and “Spring Awakening.”

What made the size of the streaming audience that much more impressive, according to Davenport, who said it was 50 percent more than his most aggressive estimate, is that it was done with a zero marketing spend.

The result flouted conventional wisdom that people won’t go to see high-priced entertainment that they can watch at home for free.

The results were so impressive that within five years, Davenport expects streaming to be as integral to Broadway as Playbill is today.

After all, the producer told The Post, 82 percent of his streaming audience said they’d pay for the same experience with another New York play.

Half of the streaming audience said they would pay between $10 and $19 to view a stream, Davenport said.

“Even at $10 a pop, that’s a nice chunk of change,” Davenport said.

“The next step is to gather everybody involved — producers, unions, artists — and figure out the best way to divvy up this future revenue stream.”

He’s confident it can be done — if only because every member of the theatrical community is as concerned as he is about bringing a new generation to the Great White Way.

“The industry hasn’t been using the most powerful audience-development tool that’s out there,” he said.

To be sure, Davenport said not all shows will be streamed.

Red-hot productions like “Hamilton,” he said, “have enough heat to keep that fire burning a long time.”

The technology is here and, as his “Daddy Long Legs’” stream demonstrated, the audience is out there. “All we have to do is stop being 10 years behind everybody else,” Davenport concluded.