He started out as a teenager spraying graffiti on walls in Paris -- but French street artist JR now communicates through giant photographic portraits plastered from Brazil to Hong Kong, a bid to reach what he feels is a disconnected world.

The 32-year-old who describes himself as a "photograffeur" -- a mix of photographer and graffiti artist -- has mounted enormous black-and-white photos of local residents on dilapidated bridges and slum walls in a bid to get his message across.

"We've come to a point in our society where we're so connected to other media and technology that it's taking away the basic essence of real human being connection," he says.  

"The whole power of this art was to gather people and reconnect people, especially in a world where we're disconnecting more and more."

Wearing his trademark fedora and dark glasses JR -- who keeps his name and identity a secret -- is in Hong Kong to present two exhibitions of his work, coinciding with the annual Art Basel show, Asia's largest art fair, which runs until Tuesday.  

One exhibition is a retrospective of his works, while the other shows images of his recent Ellis Island project in New York, where he plastered archive photographs on the walls and windows of the island's abandoned hospital.

JR has already used the city sprawl of Hong Kong as a canvas -- in 2012 he posted large black-and-white portraits of Hong Kongers on the roof of a pedestrian walkway as part of a global art project where people contributed portraits and stories.

"I love involving people... I have a lot of volunteers who come and experience the pasting of little parts of a giant photo, then they become part of the bigger adventure," he says.

"Sometimes the whole adventure of making (the art) is more interesting than the final piece itself."

In 2007, JR put up oversize portraits on both sides of a security wall in territory disputed by Palestine and Israel, adorning it with faces of people from either side of the divide -- most of them pulling comic expressions -- in a bid to bring humour to the situation.

"We want, at last, everyone to laugh and to think by seeing the portrait of the other and his own portrait," his official website said of that project, billing it as the "largest illegal photography exhibition ever".

- The world's 'best gallery' –

JR began spraying graffiti in the streets of Paris in his early teens, but after finding a camera in the city's Metro at the age of 17, he started taking pictures of his street artist friends.

"There was no social media at the time, so I pasted them on the streets... It was just the best gallery in the world you could imagine," he said.  

Since then his work has become highly collectible -- with pieces fetching tens of thousands of dollars -- and he has been compared with anonymous British graffiti artist Banksy.

The market in Hong Kong has reflected the increasing demand for street art -- two pieces by another French street artist, Invader, recently set new sales records for the artist at auction in the city.   

But JR says he is wary of commercialisation. He works with a close-knit group of friends from his teenage years and says he finances his projects with the sales of a limited number of original artworks.

"I've always been really careful -- that's why I don't work with brands or work with any commission, companies. I do everything independently because I want to protect my art and the way it gets to the people, so it's not powered by Coca-Cola or whoever."

The commercial high end of the art world is at the fore at Art Basel, with gallerists, collectors and celebrities descending on Hong Kong.

But there is also a strong grass-roots creativity in the city, highlighted during last year's pro-democracy protests.

Rally camps were transformed into open art spaces displaying everything from caricatures of the city's politicians to sculptures and gardens.  

"(Art) has really strong power at those kinds of moments because it speaks to the audience about what the people feel inside."