''If you write what I actually say, my mother will come after you and cut off your pee-pee." Occasionally, it can be hard to tell when Michael Bublé is joking, but the threat -- as weird and Freudian as it sounds -- seems earnest enough. For the past couple of hours he's been up on stage in the cavernous Events Center in Reno, Nev., rehearsing for the opening show of his U.S. tour, and things haven't been going well. His 13-piece band is finding it hard to get it together, the crew can't seem to hit the light and curtain cues, and the sound mix is muddy. Conditions are ripe for a diva fit, but Bublé has been behaving more like a teenager angling for a detention, and his between-song patter is getting progressively more profane with each new snafu. Everyone is laughing. But it's only after he's questioned the social graces and parentage of his imaginary audience and looks out into the empty seats to see a reporter scribbling away that he starts looking fussed. Now, crouched down on the edge of the stage, he tries his hand at being menacing, fails, then starts pleading not to be quoted. "Every time I say something stupid my mom calls me up and bawls me out."

The Burnaby, B.C., native's constantly running mouth and flip sense of humour have caused him enough trouble lately. There was the crack about marrying his girlfriend, the Hollywood starlet Emily Blunt (who's out in the seats studying for her role as the young Queen Victoria in Martin Scorsese's next film) that got played as a straight-up proposal in the gossip pages. Another off-the-cuff remark -- about how he was going to stay home from the Grammys because his category, best traditional recording, was awarded before the televised ceremony and was a lock for Tony Bennett anyway -- ended up playing as a peevish attack on a singer he adores. Add in earlier missteps like admitting he threw up in the garden at Leo DiCaprio's house. Or a booze-and-strippers boys' night out in the Philippines that was recounted in all its very graphic glory in a British magazine, and you get the sense that Bublé may be letting a lot of mom's calls ring through to voice mail.

The rules of the game are changing for the 32-year-old singer. He's no longer an up-and-coming kid with a nice backstory and a big set of pipes. Now, Michael Bublé is on the cusp of superstardom. His new album, Call Me Irresponsible, debuted at No. 1 on the Billboard Top 200. In just 14 weeks, it has sold close to 820,000 copies in the U.S., and 1.4 million more worldwide. The 19-city American tour is already sold out, and will be followed by a string of even larger European dates -- culminating at London's Wembley Arena in December -- and then a winter Canadian tour. All told, Bublé expects to be on the road for the next two years, hitting more than 40 countries. He's already big in Australia, Italy, Germany, South Africa and the Far East. But if all goes according to plan, by the time he finally makes it back home, he'll be a truly global phenomenon.

The Grammys debacle was a wake-up call for Bublé. After 16 years of struggling to get people to pay attention, suddenly, they are. "I said a lot of s--t before, but no one cared," he says later as we sit in his dressing room. After the story broke, Bublé spent two days at home in his Vancouver condo with the shades drawn. What really stuck with him, he says, was the insight offered by one of his managers. "She said, 'For all the wonderful things that have happened in your life, and all the wonderful things you have, you do know that fame is the worst of all.' "

It's a lot to ask, to feel sorry for a guy who's living the dream. But Bublé's greatest talent is his likeability. Five minutes of conversation and it's as if you've been friends for life. There's no hovering PR flack, or entourage. His newly acquired "bodyguard" -- a job that mostly consists of extracting Michael from the warm embraces of overheated grandmas during shows -- is an extra-large buddy from high school. More than 12 million albums sold and he's still trying to break himself of the habit of looking up the bad reviews on the Internet and brooding about them. "It sucks when someone doesn't like you," he says. "I want everyone to like me."

Jann Arden, the fellow Canadian who's the opening act on this tour, has a friendly warning for the men in the audience in Reno. "Michael's so sexy that he can turn you gay. It's true." When the curtain goes up a half-hour later to reveal Bublé at the microphone, black suit, loosened tie (Hugo Boss is a sponsor), and he launches into his jazzy cover of Leonard Cohen's I'm Your Man, the female screams are deafening. There's so much estrogen in the air that the real danger for the guys might be the spontaneous development of breasts.

Since his eponymous major-label debut in 2003, Warner Music Group has lovingly packaged Bublé as the smoky, heartthrob inheritor of Rat Pack cool. (Michael admits that one of the ways he convinced the company to sign him was his vow to "work his ass off" to fill the crooner slot Harry Connick, Jr. abandoned when he moved on to films and TV.) But a key source of Bublé's considerable charm is that he never seems to take the hype too seriously. On stage, he mugs and jokes his way through the set, relentlessly poking fun at himself. A bit of shtick about what a manly "bad ass" he is introduces a more than passable imitation of Elvis's That's All Right Mama (before he hit it big, Bublé played the King in a touring revue), which quickly morphs into a left field cover of Mika's Grace Kelly -- perhaps the campiest song of the last decade. "If this is your first show, you now realize what a dork I am," he tells the crowd.

Blunt, who has been with Bublé for almost two years now and shares his Vancouver home, says the gulf between the real Michael and the glossy image is laughable. "He's not like the music," says the 24-year-old Brit, who shot to fame last year as the bitchy assistant in The Devil Wears Prada. "He's a fart in a bottle." There's very little dancing, candlelight and flowers, she says, just lots of stay-at-home nights watching the Canucks and playing video games. "It's all right. I like a boy with food down his shirt."

That might be a defensive position. Bublé's fans can be, to put it politely, ardent. "They all hate me," Blunt says with a laugh. She tells of a teddy bear that someone handed him recently. Michael gave it to his road manager, who has a young daughter. When it arrived at the house, the girl gave it a tight squeeze, unleashing a recording of the laundry list of carnal pleasures the fan had in store for the singer. And all indications are that Blunt has it, just as bad as any of the women waiting at the backstage door. When Bublé pulls a stool up beside the piano during the Reno show and delivers a quiet, heartfelt rendition of (You Were) Always on My Mind, out in the audience, her eyes well with tears. "He's bloody good, my boy, isn't he?" she whispers.

Perhaps the most surprising thing about Bublé's live performances is how ill at ease he now seems with some of the standards that launched his career. In Reno, and again two nights later in Las Vegas, Come Fly with Me sounds more bored than Chairman of. And with the exception of Fever, the chestnuts tend to get played for laughs -- improvised lyrics, herky-jerky dance routines -- rather than romance.

In recent years, Bublé has frequently run down his first album (about five million copies sold to date) as "schmaltz" and "crap." He likes to tell the story of an interview he once did with a respected New York City jazz DJ who asked him -- live on the air -- why he didn't just leave blank space on the record instead of his note-for-note recreation of a Sinatra classic. "I knew he was right," says Michael. On the second record, It's Time, Bublé again caved to pressure for a "nostalgic" track, using the familiar Nelson Riddle arrangement of I've Got You Under My Skin. When the subject came up in the studio this time, the singer held firm. "I was like 'Over my dead body. It's not going to happen.' " Call Me Irresponsible has some of Frank's songs, but not in his style. I've Got the World on a String is breezy and Sylvester-the-cat sibilant. That's Life -- transformed into a gospel rocker -- is serving as the tour's showstopper, with a full choir joining Michael onstage every night. "It's okay to borrow things, to be influenced," he says. "But just to rip it off, just to repeat it? I think I have a responsibility to move the music forward."

It's a nice statement of purpose, but the singer and the people around him -- B.C.-born super-producer David Foster and yet another Vancouver native, agent Bruce Allen -- are canny enough to realize that people don't buy his records to feel experimental. (A full 46 per cent of Bublé's sales in the U.S. come from Target department stores.) The mantra for the new disc, says Bublé, was "growth without alienation." So along with the standards, fans get a version of Billy Paul's '70s-soul classic Me and Mrs. Jones (Blunt sings backup vocals), and an upbeat duet with Boyz II Men that stretches Mel Tormé's Coming Home Baby in unexpected directions. Most importantly for Bublé -- and his pocketbook (commercial radio shies away from covers) -- there are two original compositions: the current single, Everything, and Lost, an end-of-the-dance ballad penned with Arden and Alan Chang, his musical director. A similar song on his last album, Home, gave Bublé his first No. 1 hit in the U.S. Lost is perhaps an even more perfect Fosterian confection. By Christmas, it should be unavoidable.

With all this talk of growth and new directions, it's natural enough to wonder if Bublé might be getting ready to make a real leap of faith, and part ways with the man who made him a star. David Foster, after all, is something of a golden curse -- a man with almost unerring easy-listening instincts (Céline Dion, the Corrs, Josh Groban) -- and a cool factor of absolute zero. In the shorthand version of Michael's story, Foster gets almost all of the credit, "discovering" the singer when he performed at the 2000 wedding of Caroline Mulroney, daughter of the former prime minister. The reality, Bublé concedes, was more complex. Foster was kind, letting him hang out in Malibu, steering corporate gigs his way, but was reluctant to take Michael on as a project (Foster is also a Warner vice-president). "I drove him nuts," says Bublé. "I'd constantly drive out to his home and ask, 'When are you gonna sign me?' " A recent article in Britain's Guardian newspaper suggested Foster agreed to produce the demos only after Michael raised US$450,000 to cover the studio costs. Bublé gives that version a lukewarm confirmation, but goes on to say that the "real" story of his big break -- which he can't tell right now -- is even stranger. (A horse head in a bed? Midgets?)

Beverly Delich, Bublé's former manager, says that they did start looking around for a private investor in the summer of 2001. Paul Anka, who went on to executive-produce the first album, even had a mysterious benefactor lined up. But the "real story" Bublé alludes to seems to be a last-minute change of heart by Foster, who ended up paying for the demos himself, leaving it up to other Warner executives whether to sign his protegé.

In other words, the debt is both real and figurative. So for all the talk of "creative differences" and battles in the studio, don't expect a Michael Bublé rock opera any time in the near future. "I like to make fun of him too -- say things like 'How do you hear your music? You don't ride elevators,' " allows the singer. "But there's a reason why millions and millions of people bought all those albums." And as long as the fruits of their partnership have integrity, Bublé says he's content to let the hipsters and the critics sneer. The part of his story that people often overlook is the 10 years Michael spent plying his trade in lounges and clubs to crowds that were more interested in the price of the drinks than the guy up on stage. Street cred is overrated. "I'm not in the record business," Bublé shrugs. "I'm building a career."

It's a half-hour before a sold-out show at the MGM Grand in Las Vegas, and 7,500 bums are settling into the seats, but Bublé seems more hyperactive than nervous. Backstage, he's still dressed in jeans and a T-shirt, and vigorously stroking a room full of corporate sponsors. The crew from Kettle One Vodka appear to have been sampling the wares, so the point-and-shoot digital cameras are proving a bit harder than usual to operate. But through it all, Michael is the very model of broadly grinning patience; his professionalism underlined by the way he rises up on tiptoe just before the shutter is depressed. (Bublé says it's to stop him from leaning into the lens, and the fact that it adds an extra couple of inches in height is purely coincidental.) It's the record company VIPs that get the better lines, however. "Did you get the money I sent to you," Bublé asks conspiratorially when introduced to the program director from "Hot AC" FM in Phoenix. All the colour instantly drains from the face of a nearby Warner rep.

Bublé is becoming big business. Starbucks used Come Fly with Me in a commercial. ESPN promotes its poker coverage with his version of Feeling Good. There's already an endorsement deal with Rolex watches, and talks are under way with American Express. (Bruce Allen, seeking to further broaden his appeal, has him recording a song with rap-rockers Linkin Park.) And there's no end of official Michael products -- $20 teddy bears, $60 hoodies, limited-edition signed lithographs for $200.

The most lucrative deal he's clinched lately, however, was undoubtedly his June gig as the featured entertainment at the $6-million French Riviera nuptials of Australian media tycoon James Packer. Bublé won't say how much he got, but Elton John reportedly received $800,000 for playing at Packer's first wedding. Besides, the cash was not the only consideration. A friend asked him to play as a favour, he says, and with a guest list that included luminaries like Rupert Murdoch and Tom Cruise it seemed like a no-brainer. "It was good for my career."

Bublé's kind of funny about money. He hasn't really bought much with his earnings, choosing to stay in his Vancouver pad, and drive a plum-coloured Vespa around town. He gave Lewis and Amber, his dad and mom, a million dollars this past Christmas, and his two younger sisters $50,000 each. In past years, he's bought them cars, or antique watches. He was kind of hoping that his dad, a commercial salmon fisher, might retire. The suggestion didn't go over well. And that sort of generosity isn't limited to family. At the conclusion of his last tour, Bublé treated 45 members of his band, crew, and even the secretaries from the management office in Vancouver, to a five-day Hawaiian vacation.

But what does seem slightly odd is that Bublé's press clippings contain those types of intimate details, along with the kind of dirty laundry that most people -- famous or unknown -- choose to keep hidden. Like how Michael was unfaithful to his former fiancée, the Vancouver actress Debbie Tismuss, or how she "bawled" when he played her his new track about their failed romance, Lost. (Home was also written for her. Everything is about Emily.) Or the Q&A in the July issue of the music magazine Blender, where he talks about how much pot he smokes, and how he first got drunk -- with his parents -- at age 11.

It's all refreshingly honest. But it does provide ample ammunition for those websites and supermarket rags that trade in rumour. For example, when Michael appeared on American Idol in April as a last-minute fill-in for an ailing Tony Bennett, and delivered an uncharacteristically flat performance, there were suggestions he was drunk or high. (Bublé says he was just nervous. And that his loud sniffling during a post-song interview was the result of his oft-broken nose -- an old hockey injury.) Others read unkind things into his joyful celebration when Blunt won a Golden Globe this past winter, labelling him a "camera hog." Glimpses of the "real" Michael, crow the cynics, firm in their belief that no celebrity can possibly be as nice and forthcoming as this guy appears to be.

Bublé seems genuinely taken aback that some people think it might all be an act. "I'd have to be the most brilliant ..." he trails off. "That I would almost on purpose begin or end a relationship within the cycle of making a record? That would be scary." The real truth, he says, is that he just doesn't have a filter. Something he vows, almost daily, to change, but somehow never succeeds at.

The first night we meet, Bublé sees me talking to Blunt backstage, standing with a dozen or so other people in a chow line. "You're not writing about her?" he asks in a loud voice. "No, no, I'm serious." There's a long pause. "Because it's hard to get laid if people know that I have a girlfriend." Michael being Michael. Blessed with a sense of humour that's way more dangerous than his music. And a guy that -- for better or for worse -- seems destined to stay the same, no matter how famous he gets.

Sorry, Mrs. Bublé. And please, please -- put down that knife.