Never underestimate the ambition of Josh Groban.

A star since he was 17, the now-35-year-old singer with the increasingly manly pipes, quick wit and bearded good looks is adding a Broadway run to his resume (watch his red carpet interview at the Tony Awards below).

While Groban will first embark on a summer tour with Sarah McLachlan – which plays Chastain Park Amphitheatre on Sunday  – he will head to the Great White Way in October to star as Pierre in “Natasha, Pierre & The Great Comet of 1812” (aka “The Great Comet”)

Though Groban prefers to keep his personal life off the social media landscape, he did patiently comment that he and girlfriend Kat Dennings “are going to do the best we can” to spend time together between his tour – which runs Friday through Aug. 27 – and his arduous preparation for his theatrical debut.

Groban recently chatted from Los Angeles about how this concert in support of his “Stages” album will differ from his fall appearance at Cobb Energy Performing Arts Centre (note – a local orchestra will be used), his love for “The Great Comet” and why McLachlan gives him “goosebumps.”

Q: You’re finally doing Broadway! Why was this the right show and were you aware of it in its earlier incarnations?

A: It was off-Broadway for about a year. This was one of the most incredible shows I had ever seen. The first thing I loved was the music. Dave Malloy's score is tremendous. I love the immersiveness of it. You're looking at the stage and you think, now I have to get myself into this theater. It's the same way I feel when I walk into baseball stadium for the first time. I'm in the magic place now. That's how I felt walking into this environment.

Q: Do you think it will be a hard sell to the tourist crowd when people see that it’s based on a portion of “War and Peace”?

A: Dave chose a portion (of the book) that is very juicy and salacious and full of self-discovery. It's a very genre-bending score and as a vocalist, to be able to drift from a traditional style to folk to klezmer to rock, it's the most fun singing I've done in a long time, especially since you can take off the 'you' hat and be in character. To do it through the eyes of a character, you can leave yourself at the door. It's not dense. Even the first song makes fun of (what the story is based on).

Q: I believe I saw a photo of you practicing the accordion.

A: (Laughs). I'm working on that. A lot of the actors play their instruments onstage. There is no orchestra pit and the audience is surrounding you. There are about 300 seats on stage. There are fixed musicians who will play the entire show, and many of the actors are playing. Some people will be sitting in bar stools in front of me the whole night.

Q: What has your life been like the past few months between preparing for this and your tour?

A:  I was rehearsing 14 hours a day leading up to Tonys. It's a challenging show. There are a lot of X-factor elements. There are a lot of things I'm doing other than standing on the X and belting out a number. You don't know how the audience is going to behave near you. There are fight sequences and I'll be in a padded suit and there is a lot of physicality involved…The challenge for me - that I'm well aware of - when I step onstage (the audience's) first thought is going to be, "That's Josh Groban," and my goal for the rest of the night is for people to say, "That's Pierre." I like to be able to pull my fan base into things they're not expecting. That's when art wins.

Groban will head to Broadway this fall.

Credit: Melissa Ruggieri

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Credit: Melissa Ruggieri

Q: You’ve said touring with Sarah was a bucket list thing. What about her and her music has made you such a fan?

A: You talk about goosebumps. I've admired her singing style and piano and songwriting since I was in high school. She always hit such a beautiful nerve with me, just making the hairs stand up on the back of my neck. She was nice enough to have me sing with her at Live Aid in Philadelphia (in 2005, they duetted on "Angels") and I thought, I hope this isn't a one-time thing. The fact that she decided to join our circus this summer, we're very honored and grateful. It took a lot of confidence to say, "Hey, whaddaya say?" and this happened to be a time that she wanted to go on the road.

Q: Will there be any collaborations on stage?

A: I think there will ample opportunities for us to relive our duet experience.

Q: Since this is still the “Stages” tour, will the set list come primarily from that album?

A: There will still be songs from "Stages" that we can now do under the stars and with an orchestra, but also a mix of songs I've done in the past. As we're gearing up for the next chapter and the next journey, maybe it's time to explore some (other) songs. The summer sheds are little more laid back, people are out there having a glass of wine. I feel like the formality of the (first leg of the) "Stages" tour we can toss out the window.

Q: Last time we talked, you mentioned you were studying for your pilot’s license. How is that going?

A: I took a little bit of a breather from it - because I want to live! - and to make sure that when I continue to do it, I have many months of time. I'm just right before my first solo flight and want to make sure I have a few weeks of uninterrupted time. Maybe after Broadway.

Q: What is your commitment to the Broadway show?

A: I'll be there for many, many months. I did not want to be a drop in and leave. I've committed a very good chunk of my time.

Q: You’ve been a good co-host with Kelly Ripa (Groban most recently shared the “Live with Kelly” stage in late June). Is that a full-time gig you would ever consider?

A: That would be a very long day for me! I love doing it with her, I love the team there, they've always made me feel so welcome. They make it so fun. We've done it now 10-11 times together and it's something I always look forward to doing. She deserves to have the absolute best next to her. I have zero clue what their plans are – it's a complete hypothetical. But if I'm thinking about it, I don't think I've got time.

Q: So, if touring with Sarah was on the bucket list and you’re finally doing Broadway, what’s left to conquer?

A: My sights after that are the next record. I view each record as an opportunity to start a new chapter. "Stages" was very specific and the next one will be more eclectic and original, and maybe at the same time I can convince one of the many space traveling nations to put me on board for something (laughs).

CONCERT PREVIEW

Josh Groban and Sarah McLachlan

7 p.m. Sunday. $38-$152.50. Chastain Park Amphitheatre, 4469 Stella Drive N.W., Atlanta. 1-800-745-3000, www.ticketmaster.com .

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