This Old Dog is the current album by Mac DeMarco

PURVEYOR of slack, gap-toothed prankster and goofball prince are just three labels used to describe Canadian singer-songwriter Mac DeMarco since he broke through with his debut album in 2012.

The 27-year-old's laid-back tunes and youthful abandon have attracted a cult teen following who track his every move. Estranged from the corporate side of the music industry, he recently hit the headlines when his latest record leaked online in April and, in typical DeMarco fashion, he urged fans to download it illegally.

Born Vernor Winfield McBriare Smith IV in April 1990, Mac's mother changed his surname when he was five after giving his father an ultimatum: pay child support or they take my name. The cash didn't arrive.

After leaving school and moving to Vancouver and then Montreal, he began recording as a solo artist. Mini-LP Rock And Roll Night Club attracted the interest of record label Captured Track and they offered him a full-length follow-up. Five years on he's just released his third full-length album and, as the nicknames above indicate, built up a reputation for tomfoolery and playing tricks.

Sporting messy, tousled hair, he arrives at the door of a dressing room in London's Brixton O2 Academy with a courteous smile. Mild-mannered, humble and relaxed, the caricature only partially fits.

"People say I'm crazy or goofy or whatever," he says, "It's there, it's totally there and people seem to like it and if they want to hone in on it that's fine with me, that's great.

"It's not up to me anymore. I'm essentially a walking, talking meme so people can call me whatever they want, it doesn't matter. Like my songs they are out there, they aren't mine anymore. And this persona is no longer mine now."

He laughs off reviews of his new album, This Old Dog, which said he was maturing and getting more serious.

"It's ridiculous. They say I've been growing up for like four years or something. Who gives a shit if I'm growing up or not? All these people were like 'What?' when this new album came out. They made it that way in the first place."

A born entertainer, he pulls faces at the camera as he answers questions and litters sentences with "I dunno".

The night before, he played the first of two shows at the Brixton venue – one of the largest he's played to date – and admits to waking up just half an hour before he was due on stage.

"I was sleeping face down on the couch and woke up like half an hour before we had to play I was like 'Huh?' But there was no jitters, nothing, it was just 'Am I going to stay awake for this whole show?' It was cool and I'm glad it went that way, I felt comfortable even though it was big."

As well as his reputation for pranks, DeMarco is known for smoking a lot. Although he doesn't light up during the interview, he references the habit on several occasions, at one point staring into the camera and half-jokingly warning his young fans off taking it up themselves.

It's a half-joke because it something he really does think about.

"I have really young fans and they look up to me. People have the capacity to make their own choices and I made mine and I'm fully addicted to cigarettes and it's expensive. So if that's really what they want I guess it's really what you want.

"It's interesting young fans latch on to things; it's great because I feel like hopefully they take the good stuff too, where I'm encouraging them to be kind or brush their teeth," he says before smiling and adding: "I haven't brushed my teeth today actually but I'll get round to it."

He's dedicated to his fans in a way like almost no other star of his calibre. In 2015 he gave his New York address out, inviting people round for coffee. Fans promptly appeared at his door and he explains it quite simply: "If people want to say what's up then I'm gonna say what's up."

"I was always more enticed by the people who just seem they are more down to Earth rather than some kind of sexy, mystery stuff," he adds.

The social media habits of the young fans concern him, however.

"When I was a kid I really loved computers and I liked the programming and I was in some online communities so I understood what it used to be in a way but it changed at some point.

"People are just archiving their entire lives which is entirely fine, but the parts that freak me out are where social media PR companies are tricking kids into selling things for them without them even knowing.

"And there is so much weight and importance on something as stupid as a like. Quantifying how cool because 50 people liked this. It's a f***** up way of twisting a person's brain around."

He has introduced a new ritual during the current tour – walking out to the Godfather waltz. And it certainly seems to get him in the mood that night, saving his stage dive for the finale. Rolling back and forth above the heads of the sell-out crowd, he grabs at sips of beer and somehow manages to smoke a cigarette during the ride.

It's no surprise that DeMarco says he just finds it "really cool" that he's performing sell-out gigs and he struggles to see it happening forever.

"I'm sure people will forget about me at some point and then I'll probably still make songs because I was doing it before anyone cared.

"I just want to make simple, straight-up songs that mean something to me and then I'm happy."

In an industry of manufactured controversy, social media spats and an online gap between stars and their fans, this man is an obvious exception.

:: Mac DeMarco plays Dublin's Vicar Street on November 22 (ticketmaster.ie). This Old Dog is out now.