Dolly Parton is at her most delightful when she’s laughing at her own jokes. Perched on a leather chair in the den of producer Bob Greenblatt’s gorgeous Craftsman home in the Hollywood Hills on a mild September day, the 62-year-old country music queen punctuated an interview about her work in “9 to 5: The Musical,” which opened recently at the Ahmanson Theatre, with zingers she admittedly has used a hundred times before. She would let forth a line — “People always ask me if I’m offended by all the dumb-blonde jokes. I say no, because I know I’m not dumb, and I know I’m not blond!” — and follow it immediately with a knowing peal of a giggle. The laughter was neither self-deprecating nor vain; it was her way of celebrating the joy of shtick.

Knowing a good punch line is just one talent that makes Parton inherently theatrical. There's her look: the massive hair, superhuman hourglass figure and blindingly bespangled costumes, adding up to a cheerfully overdone femininity that's made her one of the world's most recognizable stars. There's the act she's been perfecting for upward of 40 years, a much-loved mix of corn pone and sugar. And finally, there's her songbook, full of rich narratives such as "Coat of Many Colors" and giant ballads such as "I Will Always Love You."

In light of all this, it's almost shocking that Parton's only now coming to Broadway, decades after conquering both Hollywood and the crossover pop charts. The highly anticipated musical, staged by Tony Award-winning director Joe Mantello, is scheduled to open on Broadway on April 23 at the Marriott Marquis Theatre.

Parton had been contemplating her own jump across the footlights when Greenblatt came to her with the idea of basing a musical on "9 to 5," the 1980 screwball comedy in which she made her acting debut. "I was writing my life story as a musical," she said. "Then Bob Greenblatt came to me, and he said, 'We're thinking about making "9 to 5" into a musical, would you be interested in doing the music?' And I thought, 'I've never done anything like that. I'd like to try.' "

Parton met with Greenblatt and Patricia Resnick, the writer behind both versions of "9 to 5," and went through Resnick's script. Then Parton set off to compose.

Greenblatt and Resnick, both reached by phone, said the songs were pure Dolly from the start. But they weren't pure country. Parton made one the title track of her new album, "Backwoods Barbie," and it's a vintage Tennessee tear-jerker custom-made for Parton's "9 to 5" character, secretary Doralee. But others are gospel-flavored showstoppers or novelty songs or cabaret-style standards.

Parton has crafted a collection of songs as varied as the show's three heroines: the quintessential working mom, Violet (played by Allison Janney, in the role originated by Lily Tomlin), the heart-rendingly clueless divorcee, Judy (Stephanie J. Block in the Jane Fonda role), and the feisty "cowgirl," Doralee (now played by Megan Hilty, filling some pretty big "Double D's," as one Parton song calls them).

"Dolly agreed right away that it shouldn't be a country sound," Greenblatt said. "That's not what the story or the characters require -- except for Doralee, which really is country. We always agreed that Dolly would write what she saw as pertinent to the characters. But we wanted to keep the essence of Dolly. The Dollyizing comes out in the cleverness of her lyrics, and in the spirit."

Parton uses the term "Dollyizing," too, to describe not just what she's doing to Broadway with this music but to explain her career's worth of uncontainable moves. Parton may be best known as a sort of living cartoon -- a description she embraces -- but behind the mask of makeup and plastic surgeries, she's enacted remarkable changes for country music and for women in pop.

Her hits add up to a sound that's simultaneously down-home and far-reaching. And by playing herself, as she says, in films and TV, from "9 to 5" to "Hannah Montana," she has created an image of the Southern woman that's both satirical and heartfelt.

"I listen to Dolly, and it's musical Prozac," said E! Entertainment senior editor Marc Malkin, who co-curated "Dollypop," an art exhibition paying tribute to Parton at the World of Wonder Storefront Gallery in Hollywood through Oct. 8. "It cheers me up, all the songs that she has about just comin' from nothing. There's that song from her latest album called 'Jesus and Gravity' -- who else but Dolly Parton could get this gay Jew from New York City sitting in his car in the middle of L.A with his windows down, singing, 'Jesus!' "

Parton's Oscar-nominated title track for the film "9 to 5" epitomizes her knack for the universal. Its tent-revival-worthy melody and populist lyrics suggest country, but the original's brassy arrangement gives it soul, and Parton's lyrics take on The Man as forcefully as any classic-rock rabble-rouser. Both conversational and inspirational, "9 to 5" is a song Hillary Clinton and Sarah Palin could both love, and the perfect theme for a musical.

It's always been central to the show Greenblatt began imagining about half a decade ago. "It's as big as the movie in its own way," he said. "It's the big finale of Dolly's concerts; it's her biggest song, the best known throughout the world. So the show would already have this musical signature to it."

Parton used her people skills to write the rest of the songs for "9 to 5: The Musical," letting the characters dictate their mood and structure.

"She is the least diva-ish diva in the entire world," said Resnick, who's worked with Parton not only on both versions of "9 to 5" but other projects, including the singer's last major film, the 1992 comedy "Straight Talk." "She's generous and flexible, so easy and fun to work with."

Most important for the intense collaboration that goes into making a musical, Parton is a quick study. Musical director Stephen Oremus enthused about her ability to compose on command. Speaking by phone from the theater, Oremus recalled a particularly striking incidence of deftness.

"Because of the way the story was changing, it needed a new lyric here or there," he said. "Dolly would be fine with it. She'd just say, play me the line. One time, I played it for her twice and she said, OK, I'm going to go to the ladies' room, and I'll come back with the line.' She not only came back with the line, she had several. She said, 'Here's my favorite, and here are two alternates, in case you don't like it.' "

For Parton, being flexible never meant relinquishing control. She has spent her career defying expectations and standing up for her due; it's not for nothing that she's earned the nickname "the Iron Butterfly." She's been actively involved in every step of the evolution of this Broadway-bound show, adaptable and friendly, but determined that the music remain her own.

Asked if she ever had problems with changes, she replied, "Well, if I did I would say so, because I had the right. Because it was my music. I had to have control of the music. They all respect that. But they also know I'm a smart enough girl, so that if somebody's making it better than it was, I'm going to be the first to say: go with that."

In turn, Oremus did his best to "Dollyize" the orchestrations. "We're not trying to shoehorn Dolly into the Broadway idiom," he said. "We use pedal steel and dobro, elements that Dolly loves. We've got some country fiddle in there. We've added little flavors that don't come out specifically country but give it a sense of character."

Parton couldn't be happier. And she's on to her next round of projects, which includes more touring to support "Backwoods Barbie," a possible dance music album and that still-unfinished stage production about her own life. Her future is open. Only one thing is for sure: Now that she's spent some time behind the scenes of a major production, she's ready to be back at center stage.

"I want to be out there," she declared. "I love being an entertainer. My whole life is like, 'See me, see me!' I want to be seen, I want to be loved."

If you work '9 to 5'

• What: "9 to 5: The Musical"

• Where: Ahmanson Theatre, 135 N. Grand Ave., Los Angeles

• When: 8 p.m. Tuesdays-Fridays, 2 and 8 p.m. Saturdays, 1 and 6:30 p.m. Sundays. Ends Oct. 19.

•Tickets: $30-$100.

• Info: Call (213) 628-2772.