Megan Mullally and Nick Offerman light up Goodman stage in ‘Iceboy!’ premiere

“Iceboy! Or the Completely Untrue Story of How Eugene O’Neill Came to Write ‘The Iceman Cometh’” — 3 stars

There’s a lot of star power on stage at the Goodman Theatre these days, and much of it comes courtesy of Megan Mullally and Nick Offerman, who on opening night of the deliciously silly new musical “Iceboy! Or the Completely Untrue Story of How Eugene O’Neill Came to Write ‘The Iceman Cometh’” stopped the show almost before they uttered a word.

The sustained entrance applause that greeted the Emmy Award-winners (and former Chicago actors) was unsurprising. Mullally (who played Karen Walker on “Will & Grace”) and Offerman (who played Ron Swanson on “Parks and Recreation”) are masterful comedic actors whose timing is flawless.

Mullally, whose voice sounds like a combination of Karen Walker and Mae West, is so skilled she earned applause just by reciting the alphabet.

That makes for a lot of wattage. Unfortunately, “Iceboy!” by composer/lyricist Mark Hollmann (“Urinetown”), lyricist/book writer Jay Reiss (“The 25th Annual Putnam County Spelling Bee”) and writer Erin Quinn Purcell is not yet the ideal conduit for the considerable gifts these real-life spouses possess.

“Iceboy!” sometimes feels as if the creators threw everything at the audience and waited to see what stuck. The result, at this point, is a mixed bag of a musical. But it has potential, especially if the creators give up their attempts to address Serious Issues (self-doubt, isolation, fear of abandonment) and simply embrace absurdity.

The sardonic and credibly vulnerable Offerman plays hard-drinking, self-doubting O’Neill, who narrates the tuner, which unfolds in 1939 New York City, and purports to reveal how he came to write his masterwork “The Iceman Cometh” after six years of writer’s block.

The ever-engaging Mullally plays onetime orphan turned self-involved and aging Broadway legend Vera Vimm, who purchases a frozen Neanderthal man discovered by Arctic explorers.

While Vera claims she bought the boy because she felt sorry for the motherless frozen stiff, others suggest she did it to garner headlines and boost ticket sales for her new show, “The Garment Girl.”

It’s a play about sweatshop justice by her longtime playwright boyfriend and O’Neill rival Floyd Richards, played by “Reno 911!” alum Cedric Yarbrough, whose entrance also sparked applause.

As the ice begins to thaw, the titular Iceboy (Grey Henson, a lovely tenor) emerges. Before long, he’s on Broadway, eclipsing Vera and taking over her role in Floyd’s show. Eventually, he begins a romance with Vera’s no-nonsense Gal Friday Lambert (a canny Sarah Stiles, whose performance recalls a young Eve Arden) and develops a rapport with Vera’s butler Frankenstein (Alex Goodrich) or, as Offerman’s O’Neill correctly points out, Frankenstein’s monster.

All of which leaves Vera out in the cold.

The same kind of zaniness that defined Hollmann’s side-splitting, Tony Award-winning “Urinetown” propels this show. Wisely, director Marc Bruni leans into it. Indeed, “Iceboy!” has some great gags. Unfortunately, some go on a bit too long and get a bit too bawdy.

That said, a pair of gangbuster production numbers — “Poor Little Orphan Girl” and “Hooray for Iceboy!” — bookend the show that includes the expositional “Ballad of Iceboy,” which benefits from Henson’s exceptional voice and sympathetic performance.

Overall, the songs aren’t especially memorable. The exception is Stiles’ marvelously deadpan menopause ballad in which Lambert describes the “rare and mostly unknown” condition that “doctors barely study.”

How society treats — or mistreats — women of a certain age is one of several social critiques Reiss and Purcell (lightly) address. The duo also satirize Broadway and an industry that values commercial success over artistic integrity.

The musical also serves as something of a primer on Eugene O’Neill (hailed by former Goodman artistic director Robert Falls as America’s Shakespeare) and his masterwork “The Iceman Cometh,” including character origins, setting and its underlying theme about the lies people tell themselves that keep them trapped. Or as Offerman’s O’Neill says: frozen.

In addition to strong work from the principals, Goodman’s premiere features solid supporting performances from ensemble members Donterrio, Melanie Brezill, Will Koski, Linda Mugleston, Shawn Pfautsch and Andrea San Miguel.

But really, it’s Mullally and Offerman who carry this show. Lighting up the stage, they earn every titter, chortle and guffaw the Goodman audience bestows.

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Location: Goodman Theatre, 170 N. Dearborn St., Chicago, (312) 443-3800, goodmantheatre.org

Showtimes: 7:30 p.m. Tuesday through Friday; 2 and 7:30 p.m. Saturday; 2 p.m. Sunday through Aug. 9. Also, 2 p.m. July 23 and 28; 7:30 p.m. Aug. 2 and 6. No shows July 29. No 7:30 p.m. show Aug. 9.

Running time: About 2 hours, 20 minutes, with intermission

Tickets: $54-$229

Parking: Nearby garages; discounted parking with Goodman Theatre validation at the Government Center Self Park at Clark and Lake streets

Rating: For adults; includes sexual content and strong language