He's a tenor, of course, so you'd expect Michael Philip O'Brien to be adept at hitting the high notes. But this Northeast Philadelphia native is a real high flier, able to sustain a preternatural pitch that has earned him quite a following in the musical theater scene.

Luciano Pavarotti would have been proud.

O'Brien will tip his hat Monday to his more famous Italian confrere in a cabaret show at World Cafe Live called The Three Philly Tenors, singing with two other acclaimed locals, Jeff Coon and Ben Dibble (also known as Frog and Toad in the wildly popular children's production at Arden Theatre).

The Valentine's Week show is part of a cabaret series introduced this season by 11th Hour Theatre Company, a nonprofit that O'Brien cofounded in 2003 with his sister, director Megan Nicole O'Brien, and their friend Lansdale-born actor-director Steve Pacek.

Billed as the only company in Philly dedicated solely to musical theater, 11th Hour last month wrapped up its mainstage production of the rock musical Lizzie, about the ax-wielding Borden lass.

O’Brien, 37, and his wife, Colleen, a physician, this weekend celebrate the one-month birthday of their son Caleb.

He took some time to talk to me about his blue-collar roots and his passion for musical theater.

So, who is Michael Philip O'Brien?

For the first 10 years of my life, I lived in the Northeast, and then we moved to the suburbs, to Horsham. For school, I went to Hatboro-Horsham High School … and I graduated from NYU in 2001 with a degree in acting.

Your family has deep roots here.

My parents [Raymond and Mindy] were born and raised in the Northeast. They're retired now, but my dad used to drive a UPS truck. My mom worked in a bank during my childhood, then she went back to school for [a degree in] elementary education. ... Yeah, so they're solid blue-collar Philadelphians.

Were your parents big on theater?

No. Not at all. Neither of them did theater, and we weren't a musical family, either. It was just my sister and I. But when [my parents] saw how much we loved it, they were super-supportive of us, like they were with everything else we did.

They sent you to voice lessons?

My grandfather did. He had done some community theater many, many years ago, and I guess he thought I had a good voice.

And you bloomed. You were discovered, you became a star …

… I almost quit. My career almost ended before it began.

What happened?

Six months after I started those classes, I went for an audition for a show at what used to be the Huntingdon Valley Dinner Theater. It's long gone. … I got up on stage and forgot all my lyrics and I started crying. I was 10 years old.

But luckily for me, they really needed boys, so they still called me. ... That was the beginning of everything for me.

Your sister also grew up performing?

She did some. … But in high school, she decided she wanted to be a director, and that's what she predominantly does today.

You have a deep abiding bond with the Walnut Street Theatre that goes back to this period?

I made my professional debut there when I was 11 or 12, in Jesus Christ Superstar. I was one of six kids in the show. Then, after college, I did my first show as an equity actor at the Walnut. I did Damn Yankees. And when I won the Barrymore [Award in 2009] for an 11th Hour production [of Avenue X], the awards were handed out at the Walnut. It's always been an artistic home for me.

Why did you come back to Philly after NYU? Weren't you tempted to try your luck in New York?

I lived I New York for four years, until 2003. But I kept coming back here for work because I was getting jobs here. And then we started 11th Hour, and it became my impetus to stay.

I'm sure it wasn't easy to build a new company. Why take the risk?

The first major reason was that Steve and I wanted to create work for ourselves. … This business can be very frustrating and stifling if you don't fit a particular mold, and we both felt we needed to create our own avenue as performers and directors. … We also really loved getting our friends involved in the work, giving them work as actors. And we realized we just loved creating a theatrical event from scratch.

Tell me about The Three Philly Tenors.

It's such a rare opportunity for a group of performers who bounce around from show to show in Philadelphia to get together, and I think it's especially interesting because the three of us vocally are a little more similar than we are with other singers.

You've performed together before?

Any one of us has worked with one of the others often enough. But all three of us were last on stage when we did Les Mis at the Walnut [in 2008]. Now because of a whole bunch of circumstances … each one of us got to play the role of Enjolras at one time during the run of the show. So on Monday, we'll play a sort of Enjolras medley, and we'll tell that story.

What else will you perform?

It'll be a good combination. We'll do some obscure material that might surprise people. We'll tell stories. … And we'll do some material people may already have heard us do,  you know some of the standards.

The Three Philly Tenors

7 p.m. Monday at World Cafe Live, 3025 Walnut St.
Tickets: $40.
Information: 267-987-9865, www.11thhourtheatrecompany.org.