“I never fit in,” admits Josh Groban.

Being the outcast, however, has done Groban quite well. To date, the Grammy-winning recording artist has sold over 35 million records worldwide, and next month he makes his long-awaited Broadway debut at the Imperial Theatre, where Natasha, Pierre & The Great Comet of 1812 strikes New York City October 18.

Groban’s journey began 18 years ago, when he stood in for Andrea Bocelli at the 1998 Grammy Awards rehearsal to duet with Céline Dion on “The Prayer.” Overnight, he went from 17-year-old hopeful to superstar.

“I was lucky enough to have these kind of serendipitous moments, like the one you mentioned with Céline,” he explains from the road after completing a year-long concert tour. “[They] were so fork-in-the-road for me—so unexpected for me. I grew up in Los Angeles, California, but I did not have stars in my eyes for that kind of stardom. My parents are very real-world. They’re very artistic, they love the arts, [but] were not show parents by any stretch of the imagination. They believe in education, they believe in working hard, and so my dream really was to immerse myself in theatre.

“There are unexpected doors that open that, as is the ebb and flow of life, sometimes you have to walk through them and see where it leads, and so I did. But, ever since I was very young, my dream and my goal was to eventually find myself in the world of theatre, so all of these years later—seven albums and five tours—to have made a musical theatre record, and then while I was in the process of promoting that, to have had the offer for Comet, it really was very full circle.”

The door that Groban walks through this time leads to Moscow 1812, a whimsical world ripped straight from the pages of Leo Tolstoy’s War and Peace, where drinks are flowing and the wealthy aristocrat Pierre is playing piano and accordion—searching for his place in life.

Much like Pierre, the part he plays, Groban has always searched for his seat at the table amidst a background of music and merriment.

“My career has really been a very interesting one, in that it’s been very hard to define in the media, certainly, and it’s been one that I feel [where] I’ve never been easily categorized,” he explains. “Because of that, you don’t really become a media darling, you don’t become an awards darling. You’re just left to do your own thing on your own little musical island, and so there have been times where you feel like you’re invisible out there, and you feel like really you’re doing something all alone, and you’re not part of a bigger genre [and] in a musical clique. That can be discouraging at times because it can make you feel like you’re doing a lot of work and you’re Mr. Cellophane, so to speak.

“But, generally, if I look back at the last 15 years and the ups and downs of whatever that may have caused, that was a blessing because I never had to worry about living up to any kind of false hype because there was none. I never had to worry about whatever the fad of the moment was musically because I never fit in. So, basically, I was left by complete accident to make music the right way and to start my career and continue my career really organically, which is just to do things that my gut says are great, to sing songs that give me goosebumps.”

Groban was instantly drawn to the music of Dave Malloy, who composed The Great Comet—mixing electropop, klezmer, folk and rock with musical theatre. He saw the show downtown in the Meatpacking District at a custom pop-up venue, Kazino, in its original 2013 incarnation and had his eye on the project ever since.

With Comet, he feels as though he’s finally found the perfect match, unlike the 15-year-old Josh Groban who longed to play the Demon Barber of Fleet Street in Interlochen Arts Camp’s production of Stephen Sondheim’s Sweeney Todd. As the story goes, a baby-faced Groban gave his best attempt at a menacing audition, but went home with Broom Sweep No. 3, who’s killed by Judge Turpin in the show’s first three minutes.

“I learned a couple of really valuable lessons that day,” he says. “One was that I was putting on an audition based on what I thought I needed to do to get the role…and two, it taught me to be really supportive of the cast early on and to leave my ego at the door.”

He adds, “I think it’s important we have disappointments early on—I think it’s really important, actually—because it helps you build a thicker skin for what you actually need to do in the future.”

What would he tell his 15-year-old self now? “I certainly wouldn’t tell that kid what kind of success he would have in the future because then he wouldn’t have success. I think it was important that younger me be afraid. I think it was important that younger me understand how hard it was going to be and understand how much work it would take… But I would tell my younger self to enjoy every minute more. At 35, I’m now starting to figure out the fun of taking chances.”

Michael Gioia is the Features Manager at Playbill.com. Follow him on Twitter at @PlaybillMichael.