In “Mister Benny,” a one-man play by Mark Humphrey about the beloved comedian Jack Benny, Tim Newell slips a white handkerchief into the breast pocket of his suit jacket, puts on a pair of chunky black glasses, and disappears.

In his place, the fumbling, charming, self-aware Benny – a comedian whose vaudevillian persona belongs to a distant and more innocent age – comes so vividly to life that even those with little to no experience of his work experience a pang of nostalgia for someone they barely recognize. Newell’s performance in the Jewish Repertory Theatre’s new production of the play, which was originally produced in 2001 by the Buffalo Ensemble Theatre, is one of the great transformations of the current theater season.

In a question and answer session after the play’s Thursday night opening in the Maxine and Robert Seller Theatre in Getzville’s Jewish Community Center, Newell admits that Benny has spent the decade since that first production nestling more and more deeply into his psyche.

That’s obvious from the way Newell scans the room with a sly smirk after delivering a decent self-deprecating joke, the better to extract every last lingering chuckle from the eager audience. It’s obvious from the way he’s perfected Benny’s matter-of-fact expression, another subtle tool of delivery that magnifies what should be mediocre humor to the stuff of full-fledged hilarity.

Before heading out to this production, I received an email from JRT co-founder and “Mister Benny” director Saul Elkin noting that this production was a rethinking of the original. For those who remember Benny, he wrote, it was an attempt to take it “a step beyond stand-up comedy so that the memories which are the subject of the play both deepen the man [and] nostalgia for the period.” For those with no experience of Benny, he continued, the play would be “a test of whether or not his humor, based on character rather than jokes, still amuses us.”

Does it ever.

I was a perfect test subject for the latter group, being only lightly acquainted with Benny and knowing only that in his lifelong act he claimed to be perpetually 39 years old, played the violin badly on purpose and promoted the image of himself as one of the cheapest people in the world. (A typically innocuous Benny joke, made a thousand times funnier by Newell’s sly delivery: “My idea of a vacation is to stay home and let my mind wander.”)

Newell’s performance adds up to a great deal more than the sum of its vaudevillian parts: the expert comic timing, the perfectly calibrated facial expressions and the masterful recounting of anecdotes from Benny’s time on vaudeville stages, on radio and television.

The play is expertly written to take maximum advantage of Newell’s skills and Benny’s jokes. But it has some trouble spots.

The second act, in which Benny waxes nostalgic about his love for radio and his dissatisfactions with television, drags in too many spots. One section, when Benny tears up about his wife Mary, comes at an odd place and is played weepily enough to impede the play’s comic flow. There is a good argument to be made for keeping the show to a long single act, rather than allowing the momentum to wane as it does in the second half.

Newell’s performance, though, comes close to triumphing over these relatively minor shortcomings of Humphrey’s script. At the very least, it makes you forget about them as you marvel at the inspired reincarnation of a man who defined an entire era of American comedy and then quietly slipped away.

He’s back, for a limited time only, and you’ll be sorry if you miss him.