There's a long history of stuffing famous faces into Broadway shows to bolster box office, regardless of their qualifications for the role. The revolving door of celebrity replacements in "Chicago" has become something of an industry joke. How far off can the terrifying prospect of Paris Hilton as Roxie Hart be?

There’s a long history of stuffing famous faces into Broadway shows to bolster box office, regardless of their qualifications for the role. The revolving door of celebrity replacements in “Chicago” has become something of an industry joke. How far off can the terrifying prospect of Paris Hilton as Roxie Hart be? To those of us immune to “American Idol” mania, there was no reason to expect much from an untrained actress recruited from the TV talent contest to play the downtrodden but ultimately uplifted Celie in “The Color Purple.” But Fantasia’s guileless stage presence, emotional immediacy and the parallel of her own adversity-to-triumph story make her a surprisingly satisfying fit.

Boosted by the initial announcement of her casting on an “Idol” episode, a subsequent appearance on presenting producer Oprah Winfrey’s show and a fresh ad campaign, Fantasia’s arrival has substantially pumped weekly grosses for “The Color Purple,” which after a strong start was beginning to flag a year into its run. But aside from increased ticket sales, what she really brings to the show is heart.

In original star LaChanze’s Tony-winning performance, Celie seemed an almost marginal figure. Right up until the rousing moment deep into the second act when she finally stands up to her abusive husband and seizes her independence, Celie was meek to the point of near-invisibility and vastly overshadowed by the more flamboyant personalities of indomitable Sofia and sultry juke-joint floozy Shug Avery. But from her first moments onstage as a pregnant 14-year-old struggling to understand how her sorry lot in life can be part of God’s plan, Fantasia gives Alice Walker’s story a vibrant human center.

She may not possess the technique of a more experienced actress, but the 22-year-old third-season “Idol” winner’s instinctive performance shows an unaffected sweetness and genuine vulnerability that make her absolutely right for Celie. Inevitably, wide awareness of Fantasia’s personal history as a struggling, uneducated single mother at 17 also brings strong associations to the role.

She establishes a direct line of communication with the audience that’s fortified whenever she sings, whether it’s the touching lullaby “Somebody Gonna Love You,” sung to the infant about to be snatched from her arms, or the triumphant affirmation of her existence “I’m Here.” And when her immersion in her sister Nettie’s letters from Africa prompts her to cut loose in choreographer Donald Byrd’s tribal dance, a surge of affection pulses through the house, as if the entire audience were proud parents of an awkward child stepping forward to shine.

Any graduate of the “Idol” ranks is pretty much required to blow the roof off with powerhouse vocal calisthenics, particularly so in the case of a singer like Fantasia, whose style draws from the gospel, soul and R&B greats. Refreshingly, she holds back until the appropriate moment of the show, becoming steadily more assertive only as Celie finds her voice. And when, in her final numbers, Fantasia cranks up full force, there’s no sense of a singer straining for effect but of emotions that come from somewhere heartfelt and true.

As for the rest of the show, the emphasis on comedy in Marsha Norman’s book now seems more pronounced thanks to some broad playing that at times chafes against the brutal injustice portrayed by Walker. Yet for all its lack of storytelling subtlety, the musical connects; its spiritual celebration of life has a gravitational pull that defies detachment.

Of the new cast members, NaTasha Yvette Williams delivers a big Sofia in every sense of the word, her feisty refusal to be under any man’s thumb making her a clear audience favorite. And Chaz Lamar Shepherd displays an easygoing, infectious charm as Harpo. The original Shug, Elisabeth Withers-Mendes, has upped the sizzle by several more degrees, patenting some new bumps and grinds in “Push Da Button” and bringing further warmth to her bond with Celie.

Much more than when it first opened, “The Color Purple” is now Celie’s story. And when Fantasia beams with joy and pride in the soaring final-curtain reprise of the title song, she seems as ecstatic to be a part of it as the audience is to embrace her.

The Color Purple

Broadway Theater; 1,721 seats; $116.25 top
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