Erin Mackey is the kind of cheerful colleague that co-workers love to have around. It’s not just her sweet spirit, but the homemade cakes and pies (key lime, rhubarb, strawberry) this avid baker brings to the job.

It’s a surefire way to bond with a community she’ll be part of for only three months.

Mackey, a Broadway talent who broke into show business as a body double for Lindsay Lohan in “The Parent Trap,” stars in “Sunday in the Park With George,” the Stephen Sondheim musical opening this weekend at the Guthrie Theater. This is her second summer in Minnesota — she sang and saluted as Navy nurse Nellie Forbush in “South Pacific” last year.

“The Twin Cities is like a second home to me,” the New York-based performer said during a recent pre-rehearsal stroll with co-star Randy Harrison, another New Yorker who swears he loves the Twin Cities during the shank of summer. “I’ve renewed my Nice Ride subscription, so I’ll be walking and biking everywhere. I swim the lakes. I just love it here.”

She and Harrison aren’t here to work on their tans, of course. Guthrie artistic director Joe Haj chose them to bring Sondheim’s Pulitzer-winning masterwork to life, playing the obsessive French painter Georges Seurat and his neglected muse Dot.

Mackey steps into a role originated by Bernadette Peters, the Broadway legend who is coming to Minneapolis Friday to headline the Guthrie’s annual gala, titled “La Grande Jatte Soirée” in honor of the musical.

For Harrison, who rose to stardom as a heartthrob in Showtime’s “Queer as Folk,” this is a return to familiar haunts. A decade ago he played Young Tom in the Guthrie’s production of “The Glass Menagerie.” He also showed his range as the slinky Emcee of “Cabaret” in a Broadway tour that visited the Orpheum in February.

“I’ve loved the other times I’ve been here, even though they’ve all been in the wintertime,” Harrison said behind dark glasses. “Now I get to see what friends are talking about when they say summer is the best time to be in Minneapolis.”

A tale of art that’s universal

This is the Guthrie’s first mainstage production of a Sondheim musical.

Mackey’s and Harrison’s summer idyll springs from a work about the difficulty, joys and sacrifices of creating great art.

In the first act of “Sunday in the Park,” we see Seurat at work on his most famous work, the 1884 pointillist painting “A Sunday Afternoon on the Island of La Grande Jatte,” which is now a centerpiece of the Art Institute of Chicago’s collection.

We see the power of Seurat’s pointillist vision, but also his driven, darker nature, including his chilly treatment of Dot.

“George is a better artist than he’s a human being,” said Harrison. “He’s more at home communicating with his canvas, which he loves, than the people he’s supposed to love.”

The second act takes place a century later as Seurat’s great-grandson, also an artist and also named George, collaborates with his grandmother Marie (played again by Harrison and Mackey).

Haj said the show is “about the struggle to be an artist — what’s lost, what’s gained — but it’s also a story that’s universal because it’s about the difficulty humans have connecting to each other. Sometimes we spend one too many hours at the desk, so we don’t get home for dinner. We don’t make sufficient time for each other, and yet we have this great desire to be connected.”

Among musical composers, Sondheim is notorious for being a demanding taskmaster. His songs give actors vocal workouts. Harrison and Mackey have the necessary chops, Haj said, but more crucial is their ability “to communicate deeply.”

“You’re able to read emotions through them,” he said. “There’s a transparency to what they allow you to receive and feel.”

The cast also includes a bevy of Twin Cities favorites, among them Ann Michels, Sasha Andreev, Cat Brindisi, David Darrow, Britta Ollmann and T. Mychael Rambo.

Finding Seurat

Both Harrison and Mackey spent time in France, which helped shape their characters.

Harrison learned to make cheese during his Gallic sojourn. But he doubts he’ll get a chance to show off his skills for the cast. “There’s so much to do here,” he said, noting he’ll perform eight shows a week.

Mackey visited the island that inspired Seurat (and other painters) just before coming to Minneapolis.

“It was as pretty as the painting,” she said. “You could feel that it’s special.”

Mackey is hoping to transmit that feeling to Twin Cities audiences. “This is an amazing community,” she said.

Harrison agreed.

“People who live here take it for granted,” he said. “But you should take it from someone who’s traveled a fair amount. Minneapolis is very special.”