"That was the big question: are the grey hairs gonna come and are the South Park people going to come to something they can't afford?" says Stone. "But I've seen some really old people in their laughing their asses off!"
Have they ever: since opening in March, The Book of Mormon has grossed more than $10 million in ticket sales, and has been nominated for 14 Tonys – the most of any show this year – including individual nominations for stars Andrew Rannells, Josh Gad, Nikki M. James and Rory O'Malley.
"It's been a ride and a half," says Gad. "All of us are so thrilled that the world is embracing it as furiously as they are."
After a chance meeting seven years ago with Robert Lopez, the man behind Broadway's 2004 Best Musical Avenue Q, Stone and Parker were amazed to discover that their new friend shared a vision with them: making a musical about Mormonism.
After all, explains Lopez, "religion and musicals are so close together!"
Still, in true South Park fashion, the script is rife with plenty of four-letter words, and almost all of the songs have controversial lyrics. (At one point, the ensemble directs a four-letter-word at God).
"Any dialogue is better than no dialogue," says James. "We're getting people talking!"
Plus, adds Rannells, "The show is pro-faith! It could be about any religion."
Hottest Ticket in TownAnd while O'Malley says that it's a thrill to be part of such a successful and innovative show, it does present one major problem: disappointing friends and family who want tickets.
"I was just answering my email, explaining to people I have no pull and can't get them tickets this weekend," he says. "But it's such a cool thing because people are so excited about seeing this show."
As for Parker and Stone, they're just excited to finally take a break and relax with the cast and crew at the Tony Awards this Sunday – but don't expect to see them in drag, as they appeared at the Oscars in 2000, when their "Blame Canada" from South Park: Bigger, Longer and Uncut was nominated for Best Song. (Wrote PEOPLE's Style critics of their gowns: They "don't look good.")
"It wouldn't be as funny," explains Parker.
Adds Stone with a laugh: "That's a different joke."