The show-within-the-show became the show on June 8, when the cast of NBC series “Smash” reunited to present a song-and-dance concert version of “Bombshell,” the musical whose road to Broadway was depicted in the TV series.

The one-night-only event at the Broadway’s Minskoff Theater (home to “The Lion King”) was presented as a fundraiser benefitting the Actors Fund. Looking to defer costs of the event, the Actors Fund raised more than $300,000 on Kickstarter from “Smash” fans panting to make “Bombshell” happen — and the goal had only been $50,000. “This is the largest theater Kickstarter in history,” noted Christian Borle, a cast member of the TV show (and one of the winners at the Tony Awards the previous night).

“Maybe if NBC had used Kickstarter instead of sponsors, we’d still be on the air right now,” cracked Debra Messing, Borle’s costar on the show.

Borle and Messing played the composer and book-writer/lyricist, respectively, of the fictional Marilyn Monroe bio-musical “Bombshell.” “You are about to hear the score for ‘Bombshell’ that we wrote,” she joked, referring to herself and Borle. “I’m still working on the book.”

Actually, the “Hairspray” duo Marc Shaiman and Scott Wittman penned the songs, and there never really was a book written for the show-within-the-show. So the concert strung together the pre-existing tunes with biographical texts written by Marilyn and her friends and lovers, like Lee Strasbourg and Arthur Miller.

It was all there, from the signature song “Let Me Be Your Star” to a “Big Finish” encore, with Megan Hilty and Katharine McPhee trading off in the role of Marilyn. Jeremy Jordan brought down the house with “Cut, Print… Moving On,” and the suggestive choreography in “The National Pastime” got a lot more risqué than broadcast television would ever allow. Brian d’Arcy James, Leslie Odom Jr., Ann Harada and Wesley Taylor also showed up to sing a song or two, and shoutouts were made to everyone from series creator Theresa Rebeck to NBC chief Robert Greenblatt to “Smash” executive producers Steven Spielberg, Craig Zadan and Neil Meron.

The full-length evening, which included several of Josh Bergasse’s fully choreographed dance sequences, closed with Shaiman and Wittman arriving onstage to take the mic. “What you saw tonight was the best part of ‘Smash’ for us,” Wittman said. “It was being in the room with all of these incredible people.”

The whole thing made Shaiman get downright emotional. “I hate this word on Facebook, but we are so blessed,” he said.