“It’s been like learning about family members you didn’t know you had.”

That’s how six-time Tony winner Audra McDonald described working on the Broadway musical “Shuffle Along,” which capped off the 2015-16 season with its April 28 opening. The production — full title: “Shuffle Along, Or The Making of the Musical Sensation of 1921 and All That Followed” — highlights the history and the creators of an influential Broadway musical that has been largely overlooked.

Those who did know about the show before they joined the project said they were largely unaware of its importance. “It was like the butt of the joke for me and my black friends in school,” said Billy Porter, who plays Aubrey Lyles, the co-book writer and cast member of the 1921 production. “It was a blackface show. Blackface? Songs like ‘Pickaninny Shoes’? It was like, ‘No.’ But I had no idea the history of what it had done.”

All that history provided an overabundance of material. The new “Shuffle Along” began previews running long, and was gradually trimmed down in the weeks prior to opening. Celebrating at the opening night afterparty at the Lighthouse at Chelsea Piers, the creators reminisced about some of the good stuff that audiences don’t get to see anymore.

“We had a dream ballet, but it didn’t survive past the rehearsal room,” noted George C. Wolfe, the director and the writer of new material for the book. “It was for Aubrey and F.E. [the character played by Brian Stokes Mitchell]. They ended up on the wrong side of the moon, and all these old turn-of-the-century performers were there. It was beautiful, but unnecessary.”

“I had this wonderful number where I had half blackface on,” said Mitchell, another Tony winner. “We were doing my character’s breakdown when [his partner] Aubrey left. I was kind of two characters at once, and it was a tap number, so I really got to tap a lot in it. But the number just didn’t work. And then I also got to show my a— on stage. I mooned someone. We ended up cutting it because it was redundant. It was kinda fun, but my 12-year-old son, when he saw it, said, ‘I don’t know that man.’”

“There was a standoff between Lottie Gee [the actress played by McDonald] and Aubrey at one point,” chimed in Porter, a Tony winner for his performance as Lola in “Kinky Boots.” “It was very quick, but Lottie said something to effect of, ‘Unless you’re willing to put on a dress and sing a high C, I suggest you back away.’ Well, that’s hilarious, because I already did it, in ‘Kinky Boots.’”

All that material may be gone, but it’s still there for the show’s actors. “What it’s done is that it’s given us context,” McDonald said. “Maybe it doesn’t exist anymore for you as an audience member, but we still have it as context, so it helps us, as actors, to layer in what we need.”

She’s also having a great time tapping. “I’ve never burned so many calories in my life!” she cracked.