Simon Helberg makes his biggest bang yet - as co-star to Meryl Streep

If a movie ever seemed blessed right out of the gate, it's the clever, classy, musical comedy Florence Foster Jenkins.

The true story of the New York socialite who came to be known as the "Diva of Din" after singing - terribly - at Carnegie Hall, it's powered by world-class talents. Stephen Frears (The Queen, High Fidelity) directs, and film greats Meryl Streep and Hugh Grant grace the screen as the Wilkes Barre-born Florence and her husband, St. Clair Bayfield.

But somehow - and almost miraculously - the picture, which opens Friday, truly comes alive when the leads are joined by costar Simon Helberg.

Helberg, best known for his role as a geeky engineer with a mop top on CBS's The Big Bang Theory, steals the show as Cosmé McMoon, a journeyman pianist and would-be composer from a working-class family in Mexico who is hired to accompany Florence during her singing lessons and concerts.

In a revelatory, utterly hilarious early scene, Cosmé has to audition for the job. As Florence squeaks and squawks her first notes, Cosmé's face undergoes a subtle series of transformations as he's gripped first by disbelief, then horror, panic, and bewilderment.

"That was naturally happening to me in my life at that moment as I sat there in these rooms on-set with Meryl Streep and Hugh and Stephen, and I was thinking, 'What am I doing here?' " Helberg said during a recent visit to Philadelphia.

"I was terrified," he said. "I was thinking, 'I'm in awe!' And that is exactly where he was."

Helberg, 35, whose comic roles have included a stint on MADtv and a role on Joss Whedon's web musical mini-series, Dr. Horrible's Sing-Along Blog, paused for a beat, then added, "This was a guy who was from somewhere else . . . and now he's in New York in the middle of this group of socialites, in elite high society.

"He was excited and thrilled to be in this place, but also [thinking], 'Oh my gosh, this woman can't sing! This is a total nightmare and my career's over,' " Helberg said, going into character for effect.

Florence Foster Jenkins lavishes great love on characters most people would consider highly eccentric, if not entirely mad. There's Florence, of course. And then there's Helberg's Cosmé.

A slight man who was obsessed with bodybuilding who also dreamed of becoming a composer, the pianist was a true oddball who didn't quite fit anywhere, Helberg said.

"He was most likely gay, at a time when it was illegal and certainly frowned upon everywhere," the actor said.

"But I don't think he even knew it. He seemed to have been a very naive man. I don't think he fully realized why he enjoyed bodybuilding so much and looking at [bodybulding] magazines. I thought of him as almost being an alien in his own body.

"But he also has a great strength, because he confronts these people honestly. Forced to become an accomplice [to Florence's madness], he confronts [her husband] about playing along with a wife who had no talent."

Helberg is alternately impish and panicked as Cosmé, whose outsider status he wears like a badge throughout the film.

The musical scenes, especially, glow with energy - because it was all done for real. In a rare break from usual practice, Frears insisted the actors perform all the music live on camera.

It wasn't too great a hardship for Helberg, who began piano lessons when he was 10.

"I know that's really late for kids to start," he said. "Most of them already are washed up by 10! And I didn't even want to play classical music, I wanted to do rock 'n' roll."

Helberg, who had a half-dozen refresher classes before shooting the film, said piano was his fallback instrument.

"When I was a kid, I really wanted to sing. I wanted to be in a boy band like New Kids on the Block," he said.

"But, like Florence, I think I was probably not great - because my parents smiled and said, 'You know, you might want to try an instrument.' "

tirdad@phillynews.com

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