CONCERT PREVIEW

Atlanta Symphony Gala concert with Jason Alexander

7:30 p.m. March 7. $25-$99. Atlanta Symphony Hall, 1280 Peachtree St. N.E., Atlanta. 404-733-5000, www.atlantasymphony.org.

In a 1997 episode of “Seinfeld,” George Costanza makes one of his knuckleheaded moves and records a goofy outgoing message on his answering machine to the music of “The Greatest American Hero.”

His off-key warbling is even funnier to absorb because his real-life counterpart, Jason Alexander, is, in reality, a Tony-winning Broadway veteran.

Many fans of the show are still shocked when they learn of Alexander’s pre-domain mastering career, and that classic “Seinfeld” scene (aren’t they all?) doesn’t help further the narrative.

“I really wasn’t a name when I was doing Broadway unless you were part of that elite club, so all people remember is how badly I sang on the George answering machine,” Alexander said. “It was actually very hard to film that scene because it’s easy to be way off pitch, so to be just a little bit off takes some time to get right.”

In reality, Alexander grew up in New Jersey as such a fan of show tunes — thanks to his sister’s vast record collection — that when he saw Ben Vereen in ‘Pippin’” he imagined, “I could become the white, Jewish Ben Vereen.”

It appears that being a best featured actor Tony winner in 1989 for “Jerome Robbins’ Broadway” will have to suffice.

Alexander, who primarily lives in Los Angeles with his family, is calling from an airport cellphone parking lot, having just said goodbye to his departing wife.

Yes, his voice and inflections sound like George Costanza because for nine seasons he embodied the alter ego of show co-creator Larry David.

But Alexander, 55, couldn’t be more unlike the lovably conniving, slacker-ish George.

His appearance Saturday at the fifth annual Atlanta Symphony Gala concert is tucked into a schedule that includes negotiations for “a cable TV thing”; actively developing another show that “would be perfect for Netflix”; playing in the occasional celebrity/charity poker tournament; keeping a hand in directing (he’s helmed everything from an episode of “Mike & Molly” to a Brad Paisley video to a recent musical in South Florida); honing his stand-up act that played Las Vegas for a monthlong run last year; and bringing his song-and-comedy show to cities around the country.

Proceeds from his Symphony Hall show — he was originally scheduled to perform last October but the date was nixed during the ASO’s contract negotiations — will benefit the orchestra and its education and community engagement programs.

Since many people are expecting Alexander to be funny rather than to soft-shoe his way around the stage, he’s made an effort to craft a show that is more variety-like than standard-orchestral performance.

“It’s a different night than if you were seeing Mandy Patinkin or Brian Stokes Mitchell,” he said. “I made a concerted effort to have a good deal of fun and change the perceived stuffiness of a symphony hall.”

Alexander not only peppers his act with comedy, but also does a number that involves the assistance of seven people from the audience. (“You kind of have to drag them up there — and I’m looking for specific types,” he said, so consider yourselves warned.)

One of Alexander’s major moments during his performance is his “inappropriate medley” — a run-through of familiar toe-tappers from Broadway musicals that would be least-suited to his talents.

Of all of them, Alexander said, after pausing a moment to consider his response, the role he most covets is the one he actually had a shot at — Jean Valjean in “Les Misérables.”

“After Colm Wilkinson left the Broadway show (in the late ’80s), they cast a wide net,” Alexander said with a laugh. “So I went in to audition and I hadn’t really prepared and I forgot that the song I was going to do, ‘Who Am I?,’ has a very, very big note at the end. I didn’t remember that the song ended that way until I inhaled and went to hit that note and, well … I didn’t get the part.”

Still, Alexander’s theater resume sparkles, from that award-winning job in “Jerome Robbins’ Broadway” to roles in Stephen Sondheim’s “Merrily We Roll Along” and Neil Simon’s “Broadway Bound” to a Los Angeles production of “The Producers” with Martin Short and a 2004 musical adaptation of “A Christmas Carol” alongside Kelsey Grammer.

While the combination of “Seinfeld” and raising a family — his younger of two sons is now in college — kept Alexander a coast away from Broadway, he’s hopeful that a show he’s doing in Sag Harbor, N.Y., this summer, Jerry Sterner’s “Other People’s Money,” will attract a producer for a bigger stage.

And yes, he is amused that Larry David, the inside voice of George Costanza, is currently starring in his first Broadway show, “Fish in the Dark,” which David also wrote.

Alexander said the pair had a “funny lunch” immediately after David decided to experiment with the Great White Way.

“He said, ‘Did I make a mistake?’ and I explained that he would love so much of it — assuming that it went well. But I told him, ‘I want to come see you on a Thursday nine weeks in (to the run) and see how you feel.’ I will be surprised if he has the discipline of eight shows a week,” Alexander said with a chuckle.

Alexander has yet to see “Fish” because the show is sold out to the point of breaking records — “Larry couldn’t even get me in!” he exclaimed — but no, he won’t be leaving any off-key voice mail messages for his friend, begging for a ticket.