Twelve years after opening “The Book of Mormon,” the two actors — and good friends — return with “Gutenberg! The Musical!”Josh Gad still remembers the first time he and Andrew Rannells met, in June 2010 in a Los Angeles audition suite. No matter what Gad did during their scenes together, Rannells didn’t laugh. Not once.Rannells was auditioning for “The Book of Mormon,” the new musical from the creators of “South Park.” Gad, then a correspondent on “The Daily Show,” had long been attached. The producers wanted a celebrity opposite him, and they’d invited several to these tryouts. Rannells, a replacement actor in “Hairspray” and “Jersey Boys,” was not remotely famous. Confronted with Gad’s cyclone energy, he chose stillness.“I was so intimidated. And it really upset me,” Gad said, over dinner at Chez Josephine, a theater district mainstay where Rannells, in younger days, used to work the coat check. Gad turned to Rannells. “I had that Tony locked until you walked in the door. And I still had a grudge because you beat me out for ‘Jersey Boys.’” (It was unclear if Gad was joking. Then again, Gad is almost always joking.)“The Book of Mormon” opened in 2011, to rapturous reviews, with Rannells as the strait-laced Mormon missionary Elder Price and Gad as his co-evangelist Elder Cunningham, whose laces are a lot looser. Both men were nominated for a Tony Award and both men lost out to Norbert Leo Butz for “Catch Me If You Can.” Somewhere along the way, they became close friends, which was apparent over dinner, a symphony of bits, riffs and callbacks between bites of tuna tartare and duck breast. They had ordered identical meals and identical Diet Cokes.Rannells, 45, has spent his post “Mormon” years in other Broadway shows and on television (“Girls,” “Black Monday,” “Girls5Eva”). Gad, 42, has since become a voice-over luminary (“Frozen,” Frozen 2,” “Central Park”). Now they are reuniting, one block south and one block east of their “Mormon” haunts, in “Gutenberg! The Musical!” which begins previews at the James Earl Jones Theater on Sept. 15.“Gutenberg!” directed by Alex Timbers and written by Scott Brown and Anthony King, is a farcical, largehearted duet about a pair of nursing home workers, Bud and Doug, bitten grievously by the Broadway bug. Using an inheritance and the proceeds from the sale of a home, they rent a Broadway theater for one night, hoping to find a producer for their deeply misguided and tragically under-researched original musical about Johannes Gutenberg, the inventor of movable type and the publisher of the Gutenberg Bible.“The Book of Mormon” opened in 2011, to rapturous reviews, with Rannells as the strait-laced Mormon missionary Elder Price and Gad as his co-evangelist Elder Cunningham, whose laces are a lot looser.Sara Krulwich/The New York TimesTwo old friends finding a vehicle for a Broadway return has the whiff of a vanity project. But this deliriously silly show, in which the two actors play dozens of characters and wear a combined 107 baseball caps, demands that vanity be left at the stage door.Over dinner, Gad joked (probably!) that when Timbers had sent him a photo of those 107 hats, each inscribed with the name of one of the show’s characters, he’d tried to back out.“It was too late,” Rannells said.“I know,” Gad said. “I read my contract last night.”The day after dinner, at a rehearsal space at the Alvin Ailey Extension, Gad and Rannells were stumbling through (with an emphasis, perhaps, on stumbling) the second act of “Gutenberg!” In a scene at the top of the act, as Bud and Doug introduced themselves to the audience, Rannells hit Gad in the face, perhaps accidentally.“That’s assault,” Gad said.“You walked into it,” Rannells replied. Moments later they were standing cheek to cheek, singing spooky oo-oo-oos.Rannells was wearing a shirt and shorts in complementary greens, his wavy hair reliably perfect. Gad was all in black. He was also drinking an iced coffee. Given his typical energy levels, this seemed like a bad idea. He had burst into the rehearsal room after the lunch break singing “Unchained Melody” with heavy vibrato. He also riffed on a line from “Sunset Boulevard”: “We taught the world new ways to dream.”“No,” Rannells said. He hugged Gad. Or maybe he gave him a mild version of the Heimlich maneuver. This is more or less their way, with Gad as an avatar of chaos and Rannells in smirking control.Casey Nicholaw, the director of “The Book of Mormon,” had noted this contrast. “Josh’s comedy basically just says, ‘Watch me. Love me.’ Josh is just out there,” he said. “And Andrew’s is sneaky. Andrew knows how to just hold himself with grace and dignity and then just go for it.”Each has a different process, a different style, a different affect. Collaborators I spoke with compared them to famous comic duos — Laurel and Hardy, Abbott and Costello. Gad cited “The Odd Couple.”“I definitely am more anxious than he is,” Gad said over dinner. “I’m a bundle of anxiety when it comes to learning dances. I’m a bundle of anxiety when it comes to getting lines right.” Gad said that he is also a hypochondriac and that sometimes, offstage during “The Book of Mormon,” Rannells would suggest possible diseases for him.“He’s got a mean streak,” Gad said. “I can say that now.” Rannells, sipping his Diet Coke, didn’t deny it.Despite that mean streak, a friendship endures. Nikki M. James, their “Mormon” co-star, recalled watching it begin. “Onstage, they played very different people who end up becoming each other’s best friends,” she said in a recent interview. “That camaraderie and friendship and love and sense of family, it was very clear offstage as well.”That show left them inextricably linked. “When I die, if I get an obituary in The New York Times, Josh’s name will also be in it,” Rannells said, somewhat darkly.And after they departed “The Book of Mormon,” each for a quickly canceled sitcom (“1600 Penn” for Gad, “The New Normal” for Rannells), they would often talk about how they might work together again. A revival of “A Funny Thing Happened on the Way to the Forum” was mooted. So was a revival of “The Producers.” About four years ago Timbers (“Moulin Rouge,” “Beetlejuice”) had another idea.Brown and King (“Beetlejuice”) had first conceived “Gutenberg!” more than 20 years ago. Back then, King was a musical theater intern at Manhattan Theater Club. Tasked with sifting through the slush pile, he found himself listening to home-recorded tapes and CDs of new musicals, most of them sung through by the author or authors, most of them hopeless. King thought that he and Brown could write something just as bad. Worse even.“We tried to come up with, like, what’s a terrible idea for a musical?” King said.But what began as a way to prank King’s boss evolved into something just a little more sincere. As King put it, “We fell in love with our own dumb stuff.”In 2003, Brown and King performed a 45-minute version of the show at the Upright Citizens Brigade Theater in New York. It ran for about two years. With encouragement from a producer, they wrote a second act and took it to London. The show that emerged was never about the real Gutenberg — Bud and Doug have only the vaguest ideas of how movable type and medieval history work. Instead it was a loving lampoon of Broadway wishes and tropes.Gad and Rannells’s characters in “Gutenberg! The Musical!” hope to find a producer for their musical about the inventor of movable type.Adam Powell for The New York TimesBut for the Off Broadway premiere in 2006, directed by Timbers, the creators stepped out in favor of actual actors, Christopher Fitzgerald and Jeremy Shamos, which made it feel more like a real show and less like a goofball routine written by two starving artist roommates.There had been conversations about moving the show to Broadway. Those conversations had never been especially earnest. Then Timbers slipped Gad the script, hoping that he would share it in turn with Rannells. Which is exactly what happened.With Brown and King and Timbers, the actors met for a reading in workshop in Los Angeles in March 2020, an inauspicious moment for Broadway-bound musicals. The reading went well. To succeed, the friendship between Bud and Doug has to feel ardent, unbreakable. Gad and Rannells had that.So after a delay of about three years, conversations began again. A two-person show felt overwhelming, especially one in which the actors also had to serve as their own crew, moving each prop and set piece. Gad described it as “more intimate, and yet much more insane than even ‘Mormon.’” Still, he and Rannells agreed.In rehearsal, that insanity was in evidence. The two men were playing not only Bud (Gad), the composer, and Doug (Rannells), the book writer, but also every other baseball-capped character. And they had to play them with all the naïveté and enthusiasm that newbie writers would bring, but also with the necessary skills of a practiced musical theater performer, because bad acting and bad singing aren’t funny for long.“You have to commit to doing fully lived-in characters by performers who otherwise would not be on Broadway,” Gad said.“It’s literally a hat on a hat on a hat on a hat,” Rannells sighed.Hats aside, they seemed to be having a pretty good time, particularly during one sequence where Rannells reenacted an eagle attacking a sea gull, while Gad, playing a pubescent girl, did a sexy, scary skeleton dance.It wasn’t all skeletons and sea gulls. Opening a Broadway show is stressful. “I think our actual human sweat will give us away,” Rannells said. “I’m going to be a real mess 10 minutes into the show.” Opening a Broadway show with a best friend in accidental smacking distance is stressful in a different way. But it’s also pretty nice. “Gutenberg!” is about two characters supporting each other, through thick and thin and third reprise. And as Gad and Rannells tell it, that tracks for the actors, too.“There are times where I want to fall down and just cry at how tiring the show is,” Gad said. “Then I look at Rannells and I’m like, ‘OK, he’s going to keep me upright.’”He turned to Rannells, adding, “I’m so happy you got ‘Jersey Boys’ now. Now I actually think they made the right choice.” More