As a teenager she began classical training, including a stint at Tanglewood. She figured she’d head to a conservatory, like a lot of her friends did, maybe try for a career in opera. But she booked a couple of Off Broadway plays and then the movie “In and Out” and soon she was in a series and there was never really time — for a conservatory, for college, for the commitment a musical requires.

In 2009, when she was in town gigging with her Dixieland band, the Leisure Class, Ms. Ambrose told The New Yorker, “I would love to do a musical. Something old-fashioned, probably.” And two years later she nearly got her wish, when she was cast as Fanny Brice in a Broadway-bound revival of “Funny Girl,” directed by Mr. Sher. But four months later the financing fell apart; the musical was scrapped.

“I don’t think it was about me,” Ms. Ambrose said. That’s mostly true. As Mr. Sher said, speaking by telephone, in a season already packed with revivals, the investors “couldn’t really pull together the amount of money they needed.”

Would a flashier name have made a difference in the financing? “Yes,” Mr. Sher said. “You need to have a big, giant star to carry those things in that environment.” But he didn’t want a big, giant star. He wanted Ms. Ambrose. “She could sing it, she could act it. She had all the heart you need,” he said.

Why isn’t Ms. Ambrose a giant? Back on “Star Search,” when Ed McMahon stoops down and asks her to introduce herself, she gives a heart-cracking smile and says, “I hope to someday be a great actress and a wonderful performer.”

It happened. The great actress part. The wonderful performer part. But Ms. Ambrose, who long ago traded Hollywood for a semirural cottage, has always skirted celebrity.

Early on there were a few attempts to mold her into a starlet, “narcissism boot camp,” she called it. But she never really went along with it; years ago an agent snapped at her about “not playing the game,” she said. “I’ve always just been more of an actor,” she said.