Hairspray is nearing its fourth anniversary at the Neil Simon Theatre, but time has done little to diminish its sincerity and exuberance. The jaunty musical is still a cartoonish flashback to the 1960s, when unpopular, zaftig high schooler Tracy Turnblad (Shannon Durig) turns her dream of dancing on a Baltimore sock-hop show into a movement to integrate the black and white teenage dancers on a local “American Bandstand”-like program.

Tracy is trying to do more than beat her archrival Amber Von Tussle to become “Miss Teenage Hair Spray” and integrate “The Corny Collins Show.” With her vision of a wider, more exciting world beyond her supportive family’s modest circumstances (the Turnblads live above her father Wilbur’s joke shop, the HarDe-Har Hut), she wants to lead her agoraphobic, pancake-loving mother Edna (John Pinette) into a better life. As Tracy sings to Edna, a rotund, frustrated laundress: “Hey mama hey mama/Follow me/I know something’s in you/That you wanna set free.”

While transvestite Divine was the first Edna in John Waters’ 1988 film, Pinette is the fourth on Broadway, following Harvey Fierstein, Michael McKean, and Bruce Vilanch. Pinette, a stand-up comedian who had not been in a musical before joining the national tour of the show, becomes Edna-fied with a curly wig, enough makeup to hide his five o’clock shadow, a lightweight fat suit, and a wardrobe of housedresses, gowns, and heels.

Pinette, who is heavyset (but much lighter after dropping 150 pounds since sitcom viewers saw him get mugged in 1998’s “Seinfeld” finale), said he never thought he’d need a fat suit, “which is more about shaping me as a woman.” He also never expected to work out in a gym four times a week “to play an older, fat lady. But you need stamina for eight shows a week.”

And until he leaves the show at the end of May, his eyebrows will remain plucked. Away from the theatre, he said, “When you have no eyebrows, people don’t know what’s wrong, but they’re pretty sure something ain’t right, and, ‘Maybe let’s take another elevator, honey.’”

A large part of what has made Hairspray work since its opening in August 2002 is the chemistry between Edna (a man in drag) and Wilbur (Stephen DeRosa), who is as stringbean-thin as Edna is extra-hefty.

But their love and affection are evident throughout, no more so than in their burlesque-ish dance that accompanies the madcap song, “Timeless to Me.” Wilbur to Edna: “You’re like a stinky old cheese, babe/Just gettin’ riper with age/You’re like a fatal disease, babe/But there’s no cure.”

At one point in the song, they ad-lib a few lines and play to the audience, and it’s here Pinette seizes the opportunity to make DeRosa crack up, as Tim Conway used to fracture Harvey Korman on Carol Burnett’s TV show. “Wilbur and Edna have to be a good comic team,” said Pinette, who deploys his arsenal of comic expressions to great effect. “I think we’re a great team, and he just lets me go.”

The musical, with music and lyrics by Marc Shaiman and Scott Wittman, a book by Mark O’Donnell and Thomas Meehan, and direction by Jack O’Brien, is more than the tale of the Turnblads. Its ensemble cast features two actors who are ensembles by themselves: Julie Halston plays four roles and Kevin Meaney five. Also in the cast is Diana DeGarmo, the runner-up in “American Idol” two years ago, as Penny Pingleton, Tracy’s geeky friend and sock-hop integration ally.

Halston, who plays Penny’s mother, Prudy, said, “Diana has made the role her own in a very short amount of time. She’s a very quick study.” She added, “Ever since she came in, the audience has been filled with hoards of screaming teenage girls. Nothing wrong with that.”

Although it is not a cast of huge stars, the performer with some of the most impressive credentials is Darlene Love, who recorded “He’s A Rebel” with the Crystals, sang “Da Doo Ron Ron” on her own, and backed up Elvis Presley. She plays Motormouth Maybelle, the black record-store owner with the glittery white afro wig who sees in Tracy’s incipient civil rights effort a link to her lifelong struggle for respect in a white world. “There’s a light in the darkness,” she sings. “Though the night is black as my skin.”

Pinette said, “Darlene’s wonderful. She’s got an amazing history. She sang with Elvis and now she’s singing with a fat man dressed as a woman.”

Hairspray is playing at the Neil Simon Theatre, 250 W. 52nd St. For reservations, call 212-307-4100.