The world knows Simon Helberg as the super-smart, nerdy aerospace engineer Howard Wolowitz on the long-running Emmy-winning CBS sitcom “The Big Bang Theory.”

What the world might not know is that Helberg is also an accomplished pianist, a skill he gets to showcase in the new comedy biopic “Florence Foster Jenkins,” inspired by the life of a 1940s New York City socialite who many considered to be the world’s worst singer.

The 35-year-old actor, who went to NYU’s Tisch School of the Arts, stars as Cosme McMoon, a timid piano player enlisted to accompany socialite Florence Foster Jenkins (played by Meryl Streep) as she works to achieve her dream of being a star singer.

amNewYork spoke with Helberg yesterday about the film, in theaters on Friday.

People know you as an actor, but not a pianist. When did you learn to play?

I basically just locked myself in a room and just learned how to play when I was in high school. I was about 10 when I started and I got very obsessed with music until I was about 16. I was in rock bands and jazz bands and played on the Sunset Strip and hotel lobbies. Anywhere I could. And I got very, very good. I was an exceptionally good 16-year-old pianist, but at that point, I started acting and I just played for fun. And this movie came along and I had never played classical or opera music and I hadn’t really played seriously in years and years. This was a huge undertaking, but I really wanted to be in it and they wanted the actor to play the piano. Meryl was going to sing and they had us do it all live, on top of it. They really put us to the test.

What were the challenges of playing opposite Meryl’s bad singing?

The challenges were just trying to keep up, I guess, and do the job of the accompanist, which is ultimately to elevate the singer and make them look good. But it’s sort of like dealing with somebody who is on fire, running around the room flailing, trying to keep them still. ... But they made it fun and it forced me to be present — both of us, actually — because we both had to lock in to each other. Even though it’s the accompanist supporting the singer, the singer is also locked in to what the accompanist is doing. So I was forced to be the anchor. I’m playing a character who was actually a very gifted concert pianist, so it was quite the thing to walk into, to have to be the anchor for Meryl Streep and playing someone who is actually pretty accomplished. Both are things that I couldn’t relate to. So that certainly brought some level of daunting intimidation with it.

How did you prepare to play Cosme? Is there footage of him?

There’s one interview that exists on audio tape — from right before he died, maybe a few years before. So he’s a lot older. It’s about 7 to 8 minutes long, and in that he talks about Carnegie Hall [where Cosme and Florence eventually perform] and there’s certainly a little bit of an air of cynicism, and a snide sort of looking down the bridge of his nose at this woman. That was something I never wanted to be, in any shape or form, a part of this character. And because this script was so brilliant and Nick Martin created such a vivid character, I wasn’t at risk for that. The other actual information is very sparse and most of the good stuff was in the movie, him being interested in body building and hinting at him being gay. It all to me added up to this innocent, naive, chaste little fellow who probably was completely unaware of his own sexuality. .... Just picturing what it would look like for this guy to enter a world of cosmopolitan socialites — he’s going to look like a lost little bird probably.

Have you met anyone like Florence?

Sure, I think there’s tons of them — the farther away from the set is where you find them, in the coffee shops and near the sets. People that are somewhat deluded and the socialites exist, absolutely, everywhere you go in big cities. The people that want the attention and enjoy the glamour of it ... What she has that distinguishes her from some of that is the desire to do it is so overwhelming and there’s so much joy that she gets from it. There’s no bitterness. She’s unaware of how she sounds, so she thinks she’s a great success. In fact, she actually is a great success. It’s astonishing that she achieved what she did without any ability.

How was it working with Meryl?

It was a joy, as much joy as Florence takes in singing, the set was filled with that awe from everybody, just being around Meryl.

Actors in long-running shows can sometimes get typecast. This role is vastly different from Howard, but have you had to deal with that issue?

I think that it’s hard to be fully, again like this movie, aware of what other people presume you to be. From my vantage point, I’m an actor who got hired to play a character. I’ve had the fortune of playing that character for almost 10 years. I guess the flip side of that is people just might easily write you off as being that character — even people who are smart enough to know that actors play roles. That can happen. Doing this movie, aside from all of the other incredible things — aside from what a wonderful experience it was making it and doing it and playing this guy — it is nice I get to do something wildly different. Just selfishly, I like it because I’m an actor and I want to stretch different muscles. ... I don’t actively feel any pigeonholing, but I actively know I’m guilty of doing it too.

You went to college at NYU. Are you nostalgic being back in New York?

I guess I tend to be downtown. I’m actually looking at Central Park right now and my first experience here in the city is right where I am now, on Central Park West. I thought, “I love New York,” and I went to Tower Records [and I thought], “This is where I want to go to school,” it’s the biggest Tower Records I’d ever seen. And I then went to NYU and I lived in the Village and fell in love with the Village. The city was always magical for me and it felt like it pushed me to be better at what I was doing, because it felt very unforgiving I guess, but kind of in an inspiring way. It’s a magical thing to be back up here where I decided to go to college because of a record store and to be where I am now — driving through the Village today to get here, I saw posters for the movie near where my dorm was freshman year.