“People often ask me: Seth, when did you begin deconstructing?,” says Seth Rudetsky in his hi-larious one-man show, Deconstructing Broadway, which played two performances this weekend at the Music Theatre Company space in Highland Park. “That’s like asking me,” he says with a raised eyebrow and a shade-throwing glare, “when did I begin being critical?”

For those who don’t know, Rudetsky’s a highly respected Broadway musician and host of Broadway Sirius Satellite Radio. He also served as a writer on The Rosie O’Donnell Show and as artistic producer and music director of several Actors Fund concerts, including a 2001 concert of Dreamgirls that starred Audra McDonald (not MacDonald as listed on his bio – Seth: fix that!) and Lillias White, which resulted in one of my all-time favorite cast recordings. His infectious personality and savant-like talent has evolved into a sort of side-career where he travels the country doing this show as well as hosting a master class for up-and-coming musical theatre performers.

His life-long obsession in analyzing the voices and performances of Broadway musical theatre divas is the basis for this show. In the hands of anyone else, such a thing could be an insular “showqueens only” evening. But because the guy is so smart, quick and energetic, even people who have no idea what the hell he’s talking about find themselves LOL-ing. And for those of us who do know what he’s talking about, he’s like a superhero of showtunes.

For the first 20 minutes or so, he gives everyone a crash-course in deconstructing: the difference between chest and head voice, what it really means to sing flat (with a dig to Randy from “American Idol” who randomly calls people “pitchy” – “You’re an idiot!”), what riffing is and how it can be used both tastefully and excessively.

What makes the show are his ample examples via audio and video. For example, Janis Paige, courtesy of the original Broadway cast recording of The Pajama Game, makes audio appearances in demonstrating flat singing, and, one of my favorite new terms of the evening, “amnesia vibrato,” where her horrid performance is forgotten about because of her “a-mah-zing” vibrato that ends the phrase. And, because he’s a musician by trade, Rudetsky often turns to a piano to bang out a phrase to demonstrate another deconstructing technique.

My favorite deconstructions, however, were not of any Broadway beltress (a word lifted from Rudetsky’s lexicon), but of Rudetsky himself. At eight years old. Yes – he brought along recordings of himself as a young boy growing up in Long Island belting out “Ooh! My Feet!” from The Most Happy Fella and “Tomorrow” from Annie (complete with Sarah Vaughan-esque “riffing”) which he recorded for a pen pal, but ended up keeping because he thought he sounded too good. He says before playing the unearthed clips, “Be warned: there are many lessons to be learned here.” The result is side-splitting.

The man’s energy is contagious, and the sold-out audience gave him an enthusiastic and much-deserved standing O. Brava!

I have to tip my hat to producer Missy Greenberg for bringing Rudetsky to the 100-seat Music Theatre Company space in Highland Park (the former home of Apple Tree Theatre). I believe Rudetsky could easily fill a place like the 500-seat Broadway Playhouse in the Loop (he has quite the fan base), but we’ll take him in Highland Park. Next, Greenberg’s bringing in Miranda Sings — a performer and YouTube sensation I’ve loved since discovering her a year and a half ago — to the Music Theatre Company space Nov. 20. I’m so there.

A sample of Seth: