LOS ANGELES—“Is this thing on?” Steve Martin says, much too loudly, into the obviously live microphone set up to receive him. He thumps it solidly a couple of times with his finger, producing a dull, amplified thud, and people laugh, because, well, it’s Steve Martin, and that’s what you do.

It’s the kind of thing you’d expect from him at the Oscars, maybe, where cracking people up is the gig, and Martin, one of the most loved comics of all time, might be the best there is. But the Oscars this is not, and the jokes end here.

Martin’s speaking at the preview for The Idea of North, an exhibition of 30-plus paintings by Lawren Harris at the Hammer Museum, an intimate jewelbox of an institution at the foot of the University of California, Los Angeles’s toney Westwood campus. And when it comes to Harris, the bandleader for the Group of Seven, Canada’s national artistic brand, for Martin, it’s serious stuff.

Two years ago, the Hammer, along with the Art Gallery of Ontario, announced that Martin would curate a Harris show to be co-produced by the two institutions. (The Boston Museum of Fine Arts will also host the show before its final stop here at home in July 2016.) The idea of a Hollywood novelty act — actual curators shouldering the load while the star soaked up the predictable celebrity rubbernecking — was an easy conclusion to which to jump.

But Martin, 70, is a different kind of celebrity. “We followed his lead,” says Andrew Hunter, the AGO’s curator of Canadian art, who worked with Martin and Hammer curator Cynthia Burlingham on the show.

“One of the things that impressed me right out of the gate working with Steve was that he wanted to see everything — in person. There was no, ‘Oh, could you provide me with a list and some pictures?’ Not at all. He looked hard at the work — very, very seriously.”

Martin is an old hand in the art world. He’s been collecting since the early ’70s; at its peak, his collection included significant works by Abstract Expressionist superstars like Willem de Kooning and Franz Kline. For a 1981 Rolling Stone cover, Annie Leibovitz famously took a photo of him in a white tux smeared with black paint in front of a big Kline canvas. He wasn’t just a collector: Around that time, he even dated superstar artist Cindy Sherman.

Since then, Martin’s taste has shifted to focus on early Modern American masters like Georgia O’Keeffe, Rockwell Kent, Charles Sheeler and the core of his collection, the sombre American great Edward Hopper, whose pervasive sense of isolation he believes Harris shares. (At the preview, Martin deflated his collecting exploits. “Don’t be under the illusion that I have this massive art collection. I don’t. I have a few nice pictures that I’ve collected over 45 years,” he said, and then smiled. “I also have some terrible paintings. But I still love them.”)

And then there’s Harris, who he sees as a natural confrère to those American icons (for the record, Martin owns three Harrises, none of them in this show). A Canadian icon, Harris was all but invisible in America, a fact that Hammer director Ann Philbin drove home at the preview. “Steve had known his work for decades,” she said. “I had never heard of him. I was struck by the astonishing beauty of the work, and how completely unknown in America he was.” Burlingham added that the last time a Harris painting had been seen in Los Angeles – not at Martin’s house, at least – was in 1926. “So that gives you some idea,” she said.

Philbin, a friend of Martin’s, had invited him to curate many times over the years, but Martin had always demurred. Then, at a dinner party at Martin’s house, she spied a Harris painting on the wall and asked who had made it. And so the dots were connected: Martin would curate a Lawren Harris show, and maybe America would finally know what he had known for years.

Martin’s enthusiasm borders on the giddy, though he’s doing his best to keep it curbed. “I’m trying not to sound like an evangelical preacher,” Martin says. “But we’re trying place Harris in a new position, and when you see the show, you’ll see that it’s valid.”

Teaming with Burlingham and Hunter, the three covered the country from coast to coast, spending whole days in the vaults at the National Gallery in Ottawa, or the McMichael Canadian Art Collection, the Vancouver Art Gallery, the Art Gallery of Hamilton and even little Museum London in London, Ont. Martin was squired to the Mendel Art Gallery in Saskatoon by his old pal Martin Short, with whom he was touring a show called “Steve Martin and Martin Short in a Very Stupid Conversation.” The show was in Calgary; they made the Mendel jaunt en route.

“I really loved that part: flying to these little places, driving to these little places,” Martin says, then pauses to rethink. “I mean, they’re not little,” he says, in a very apologetic, Canadian way. “But they’re out of the way.”

How did Martin come to love a painter his entire country knew nothing about? Look at his history. Martin’s been back and forth across the border for more than 40 years, driven mostly by his connections to Canadian comedy peers like Catherine O’Hara, Eugene Levy, John Candy and Short. (Short in particular is a longtime best friend; Martin’s Twitter feed is lousy with images of Short: out for dinner, lounging with Martin’s dogs or in black tie at the Saturday Night Live 40th anniversary.)

Martin’s first solo TV special, bizarrely, was a 1974 show called The Funnier Side of Eastern Canada, paid for by a Canadian airline to promote tourism to Toronto and Montreal (fuzzy YouTube clips show Martin taking selfies with Toronto City Hall, or wandering through downtown with a request and skates on his way to play “ice tennis”).

Along the way, at bookstores and at friends’ houses, Martin indulged his interest in art. The Group of Seven, a coffee-table book standard, sunk in. But Harris stuck and took root.

After years of having the artist’s images affixed in his mind’s eye, about a decade ago, he took a flyer: He wrote a letter to Ken Thomson, the late billionaire and patron saint of the Art Gallery of Ontario, confessing his affection for the painter. Thomson, of course, was Harris’s most devout and prolific collector, and they found common ground.

“He just said, ‘Come on over,’” Martin recalled. He arrived in Toronto to find the works in Thomson’s office building on Queen St. They were being prepared to be donated to the AGO, where, along with the rest of the Thomson collection, they would form the backbone of the museum’s collection.

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“He had them in storage, but they were presented for me,” Martin said. The two men exchanged enthusiasms, communing over Harris’s heroic visions and his devotion to pushing a conventional genre into the modern world. It was the first time Martin had seen the works in person. “I was completely taken with them,” he says.

A decade or so later, Martin sits in the Hammer Museum bookstore in an armchair shoved near an entrance display, and the unceremoniousness of the whole affair seems to match Martin’s low-key, almost bashful demeanour. He seems less Hollywood icon here than devout art nerd, which the best of the curatorial profession always are.

“This is so thrilling,” he says. “(The show) looks exactly — exactly — like I hoped it would, so if anyone has any problem with the artist, it’s my fault.”

The laughs are few, though I get a big, hearty one when I suggest that the show might in fact be an elaborate sting operation to snare illegal Canadians living in L.A. when they’re drawn to such an elaborate display of Canadiana — all icebergs and glaciers and snowy mountains — so far from home.

But Martin turns quickly serious when talk turns to Harris as a nationalistic chestnut. “We’re trying to present Harris as a Modernist painter, an international painter,” he says, putting on his curator’s cap. “I think there are members of the Group of Seven that transcend the label of regionalist painter and Harris is chief among them. Harris took the landscape and he kind of abstracted it.” He pauses. “I’m looking for the right word and that’s not it. But he’s made them less organic and assembled them as forms.”

I suggest to him that if nothing else, The Idea of North might result in him being conferred honorary Canadian status and he laughs again.

“Yup, that’s what I’m going for,” he says and turns serious again. “I love this work. I’ve never seen anybody paint like this before. I really think Harris was accomplishing something and it was big.”

Big enough for those high-modern icebergs and snowy peaks to make a dent in the American art world psyche? Martin hopes so. “I believe in this work,” he says. “It’s time for Harris to sit where he belongs.”