MONTREAL - So, it seems Celine Dion is a bit of a deli diva.

Maybe that would surprise some considering one of her biggest hits is "My Heart Will Go On," but the pop megastar has a history with smoked meat that extends way beyond her new investment in Schwartz's, Montreal's most famous purveyor of the fatty delicacy.

In the old days her hankerings for smoked meat would occasionally take her to the spot across the street from Schwartz's -- The Main deli which is now, ironically, her competition.

That hop-scotching from one smoked-meat joint to the next places Dion in a rich culinary tradition, as Montreal residents have spent countless hours comparing and debating the merits of their city's old-style delis.

Which is the most famous? Schwartz's, surely. Which has the longest lineups? Again, Schwartz's. But which serves the best smoked meat? Well, that's a question that has made mouths salivate and had fists pounding a few vinyl tabletops in animated diner conversations.

"Montreal is one of the greatest deli cities in the world," says David Sax, author of 2009's "Save the Deli," which looked at the phenomenon of delicatessens around the world.

"There's nowhere that has an abiding sort of passion for Jewish delicatessen in a way that Montreal does. It's certainly on a par with New York, if not in some respects bigger and more deeply ingrained into the culture."

Like New York, Montreal was a focal point for early 20th century Jewish immigration and various histories indicate the creators of smoked meat came from Eastern Europe, particularly Romania.

The details are vague but some credit Ben Kravitz, who founded Ben's De Luxe Delicatessen in 1910, as the inventor, curing the briskets with methods he remembered from Lithuanian farmers. Others include butcher Aaron Sanft, who made the meat Romanian-style.

Until Dion came around, the closest that the dingy Schwartz's got to the glitz of showbiz was a musical based on it, a couple of movies, and the stream of heavyweight entertainers who have sidled up to its timeless counter.

Frank Silva, the the eatery's manager since 1999, thinks Dion and Schwartz's go together like, well, smoked meat and rye.

"Why not?" says Silva with a smile. "She's a Quebec icon and we're a landmark. I think we make a good team."

Debates on who serves the best smoked meat can be as passionate as any ever heard in the House of Commons -- at least to smoked meat lovers.

It's Schwartz's, it's Dunn's, it's Lester's, it's The Main, they argue.

Norman Spector, a former chief of staff to Brian Mulroney when he was prime minister, weighed in after he questioned on Twitter whether Schwartz's was the best. Schwartz's was good, he agreed, and the now-defunct Ben's was a favourite of students.

"But the secret known to only a few mavens is that the Snowdon Deli on Decarie has the best smoked meat sandwich in town (one must ask for the old-fashioned and by no means lean) and the lineups are a lot shorter," he wrote in an email.

Francis Morin, an Ottawa resident who has been coming to Schwartz's for the last 30 years, is a fan not only of the thickly stacked sandwiches but also the timeless atmosphere.

It's a place that seems untouched by the passing decades, where customers are practically jammed cheek to jowl in tables along the wall, amid furnishings accumulated over generations.

"The atmosphere, it's unique," said Morin, who always orders the medium-fat sandwich. "It's a fantastic place. I've always said if I have time in Montreal to do just one thing, this is what I do."

One man, who declined to be interviewed but said he'd been a judge at numerous local competitions to declare the best smoked meat, gave his nod to Smoke Meat Pete: "You can't beat Pete's meat," he said, invoking the restaurant slogan.

Word of Dion's new venture hasn't hurt the competition across the street at her old stomping grounds, says Pete Varvaro, owner of The Main.

That's partly because Schwartz's international renown -- it's currently listed at No. 9 on the Lonely Planet website's list of 660 things to do in Montreal -- often tends to cause world-class lineups.

That can have spillover benefits for the less-famous spot across the street. The last few months, which are usually quiet periods, have been busier than usual, Varvaro said.

"When they wait in line, they don't want to wait," he said. "So they come and try ours and they like it and they come back."

It's been happening for a long time, he adds.

Just ask Dion and her husband.

Varvaro, whose son owns the Smoke Meat Pete deli, remembers well how a 16-year-old Dion and Rene Angelil would slide into a booth at his place.

"They used to come in to eat the smoked meat, they liked the baby back ribs," said Varvaro.

"There was a place that the two of them sat, it was right in the corner," he said. "Very nice person."

He noted that Dion drifted off as her fame grew and she got involved in yet another smoked meat-serving venture, the Nickels chain. He said that even though Dion wasn't a regular anymore, she often sent regards through manager Ben Kaye, who has since died.

The mystical meat platters of St-Laurent Boulevard have had other prominent admirers.

The late author Mordecai Richler humourously described Schwartz's cut in his novel "Barney's Version" as a "maddening aphrodisiac" that should be sold as the "Nectar of Judea."

Artistic jack-of-all-trades Leonard Cohen is one of the celebrities who stops by The Main when he's in Montreal and Silva rattles off a list of names that sounds like a Hollywood phone book when he cites some of Schwartz's customers, including Halle Berry -- "one of my favourites" -- Angelina Jolie and funnyman Tim Allen.

And that's not counting the list of Canadian politicians that have chowed down on smoked meat there and other delis.

Paul Martin, when he was prime minister, was a paricularly avid consumer, choosing to mainstreet in Ben's delicatessan during one campaign and bringing bags of Schwartz's sandwiches to passengers on the Liberal plane during another.

Prime Minister Stephen Harper visited the deli when he was Opposition leader. It was also a campaign stop for the NDP's Jack Layton. Pierre Trudeau was a more regular deli customer, known to wander down from his law office to the now-defunct Ben's.

So, about that nagging question: Which one's the best?

A sampling of some of Montreal's fabled smoked meat doesn't yield dramatic differences in taste. Spices give some a slightly sweeter flavour, marinating and smoking may give others a peppery tang.

"It's the brisket," says Silva, of Schwartz's. "We marinate it with home spices -- a secret blend, of course -- for 10 days. And we smoke in-house for approximately eight hours. Then we steam it three hours and we hand slice it. Against the grain, very thin and very fast, of course."

Diane Bass, co-owner of The Main, says the cutting is key and notes the brisket comes in three parts -- lean, medium and fat.

"The grain of the brisket goes different ways. If you have a good smoked meat cutter that knows how to turn his brisket every time he's cutting, it won't get stringy."

But Ian Morantz, owner of the Snowdon Deli, has a theory on why Montreal smoked meat is so unique and has never been completely replicated anywhere else: Montreal's water.

"Water is a big factor in most recipes," he says, explaining that water composes the major part of the pickling brine before the meat is smoked. "Every region has different minerals in its water. It's still clear, pure water but it's not the same water."

Baguettes made in Paris taste different than those made in Montreal using the same recipe, he said citing one example. So do Montreal-style bagels made in Toronto.

"Everything else is the same except that the water they're using is local water and it creates a little different texture, a little different taste."