BEFORE anyone could put him on a pedestal, Jerry Lewis was already elevated in a tall director’s chair here in his dressing room suite underneath the Tennessee Performing Arts Center. Yet from this height, in a chair with his name embroidered in red stitching across the front, he insisted that he was not here to be idolized, not by his fans and certainly not by the company he is directing — yes, directing — in a coming stage-musical adaptation of “The Nutty Professor.”

He was dressed in a black shirt monogrammed with his initials and black loafers bearing the masks of comedy and tragedy. But aside from these flashier affectations of showbiz, Mr. Lewis, 86, made little effort to disguise his fragility. He used a mobility scooter to navigate the labyrinthine arts center and wore a pair of earphones connected to a microphone to help him better hear an interviewer’s questions.

He has not directed a feature film since the 1980s. He appeared on Broadway only once, in 1995 as the diabolical Applegate of “Damn Yankees,” and has never previously overseen a work of musical theater.

But in a dry voice that resonates with every word of goofy gibberish and “Hey lady!” it has ever enunciated, Mr. Lewis made it known that certain universals applied from his decades of experience.

“Everything I’ve ever done comes from here,” he said, pointing to his heart. “The times that it came from here,” he continued, pointing to his gut, “didn’t work.”

Asked if he relied on instinct to determine which part of his body is signaling him, Mr. Lewis replied: “Absolutely. And then there are times when that fools you.”

The same personal compass that helped Mr. Lewis amass a film résumé that reads like a one-man monument to comedy — “Cinderfella,” “The Errand Boy,” “The Disorderly Orderly,” among so many — has led him to this improbable point.

When the “Nutty Professor” musical begins performances at the arts center’s James K. Polk Theater on Tuesday, it will have a score by Marvin Hamlisch, a book and lyrics by Rupert Holmes, and a mostly unknown cast, including Michael Andrew in the dual role of the nebbishy title character, Julius Kelp, and his superlatively smooth alter ego, Buddy Love.

The musical, whose backers make no secret of their desire to bring it to Broadway, is also arriving without an established theatrical producer and with many unanswered questions. And though the endeavor may tax Mr. Lewis’s infirmities and could even tarnish his reputation, he is acutely aware of these perils and as eager as anyone to take them on.

“I’ve got news for you,” he said, his voice growing firm and loud. “There’s something about the risk, the courage that it takes to face the risk. And I feel very good about it. I’m not going to get greatness unless I have to go at it with fear and uncertainty.”