• Courtesy Of Emmy Walden Fox
• Josh D. Smith and Georga Osborne

The story of a tone-deaf socialite who gives singing recitals could be a one-note joke, but the Grange Theatre's production is a funny and sweetly moving duet for two engaging characters. Souvenir: A Fantasia on the Life of Florence Foster Jenkins is Stephen Temperley's dramatization of the real-life vocalist's tragically bad performing career, as told through the eyes of her accompanist, Cosme McMoon. It's a comedy that cleverly swings between high and low humor, and the performances are as polished as the gleaming baby grand piano onstage.

Audiences were drawn to witness the folly of the talentless Jenkins in the 1930s and '40s. Viewers of Souvenir get the same train wreck of awful opera, but with a comedic look at what it means to believe in oneself a little too much.

Jenkins couldn't hit a note except by accident, but she performed to ballroom crowds, sold a record she called "a lovely souvenir" of her voice and made it all the way to Carnegie Hall. She abides on YouTube still, and her story has been told in several plays and films.

Her society friends stuffed handkerchiefs in their mouths to keep from guffawing, but Jenkins mistook this for rapture at her efforts at soprano coloratura. Her extravagant performance costumes were shake-your-head-in-disbelief kitsch.

Souvenir is framed as pianist Cosme's remembrances, but his narration soon gives way to enacted events. He sets the tone by puzzling at his dozen years accompanying a dreadful singer. "People used to say to me, 'Why does she do it?' I always thought the better question was 'Why did I?'"

When they first meet, Florence tells young Cosme of her musical passion and artistic repertoire, then offers him a job as her accompanist. She's rich, he's poor, and this seems like the big break he's been looking for. Then he hears her sing. Summoning deep reserves of courtesy, he notes that she "may not yet be entirely secure in the notes." But she can no more hear the criticism than she can the cringe-inducing tone that she believes to be a glorious F above high C.

Does self-worth come from within or without? Florence seems to have an ample supply, but it still requires validation by her audiences and Cosme, and all of them are deceiving her. She came from a wealthy family, and money is one neat insulator against criticism. Her society friends feigned delight at her singing and encouraged her to give recitals. She was so bad that she developed an audience willing to marvel at her ability to stand on a stage and fail.

Being sure of oneself is either a superpower or a kind of blindness. Florence shows exactly the attitude any artist needs, but she can't complement it with talent. Cosme wonders if she's deluded or just spectacularly self-assured. As he doubts his own ability to advance his career as a composer, he starts to admire her confidence. The play is the story of her effect on him, for good or ill.

ArtisTree's Music Theatre Festival artistic director Josh D. Smith plays Cosme, grounding him in a gentle demeanor. Too kind to crush Florence's dreams, he gives her what she wants. He winces when she sings, then masters his expression and supports her fantasy. It's generous, but Cosme has a delusion of his own, believing that his financial dependence on Florence is a fair exchange for a good life, even if he isn't making a name for himself as a composer.

Cosme often does his narration at the keyboard, recollecting as he plays. He's partial to the 1928 tune "Crazy Rhythm," and Smith sings and plays a few bars to summon his memories. With variations in tempo and tone, he uses the same song to evoke hot jazz, earnest longing, misty reverie or a fierce call to action. Smith's fine piano proficiency is easy to overlook, but his playing quietly anchors the musicality of the show.

Georga Osborne, who has played the role of Florence at several regional theaters, has just the combination of acting and singing skills to capture all of Florence's inner and outer life. She is comfortable in the mannerisms of high culture in the prewar years, moving with the fussy deliberation of an aesthete meticulously stalking beauty. With her hair permed into 1930s coils and an expression of near-constant delight, Osborne gives Florence a serene sense of worth.

Behind Buster Keaton's clumsiest rubber-legged pratfalls was the grace of a dancer. Florence's woeful singing also needs real talent to produce. Osborne is a fine singer with a genius for getting Florence off rhythm and out of tune, setting her notes scraping in the air. When she tosses a maraca from one hand to another, she's so far behind the beat that she's in an alternate universe.

Director Maggie Mancinelli-Cahill elicits tender performances, and we can see Cosme's sweet blend of affection and exasperation and the little chinks in Florence's self-confidence. David Rigler's fine set, Alex Stevens' precise lighting and Rider Q. Stanton's effective sound create a beautifully realized production. Costume designer Amanda Lee supplies a parade of impressive garments worthy of a diva.

In a powerful scene, Cosme feels he must make Florence see her limitations. He challenges her to hit a note correctly and explodes with frustration when she can't. He finally pushes her too far, and the two characters balance for a moment in the no man's land of shattered illusion. Has he rescued her or hurt her? It's great theater and rich comedy. Florence is both fool and inspiration, oblivious that she's been the punchline all along. For a moment, the laughter in the audience dims, then rises again.