London - Clad in a stylish, black zip-up top and coolly holding the gaze, he has the look of a high-class hitman on the way to his next job.
But look a little closer at the slim, bearded man photographed on the New York subway and you might find a clue to his real identity.
For the mystery commuter is none other than Google co-founder Sergey Brin - wearing a prototype of the augmented-reality spectacles that he hopes will become the next must-have gadget.
They might look a little like over-sized ski goggles, but Google Glasses are tipped to be the first major breakthrough device in the cutting-edge field of “wearable computers”.
The glasses, which have been developed in secret by technologists at the Californian firm, have a screen at the side of the right eye which displays information about what the user is seeing. They use GPS and Google search information to recognise buildings and locations and display relevant data.
The spectacles, which are not to be confused with Google Goggles, an app for its Android operating system, also contain a mini-camera, allowing users to upload photos of anything in their gaze.
It is believed the technology could ultimately be combined with facial recognition software to alert wearers to the identities of people they meet in the street.
Google executives claim they could transform our computer habits beyond even the astonishing advances of recent years.
They first received an outing last year when 39-year-old Brin, who is in charge of developing Google X projects - wore them at an event for the blind in San Francisco, in April last year.
A short video produced by Google at the time showed a user's perspective as they explore New York, speaking commands, taking pictures, getting directions and receiving messages from a friend.
More glimpses of the glasses were seen last summer, setting tongues wagging in tech circles, where there was intense excitement about their potential for increasing interaction with the web on the go. But they looked chunkier than the pair spotted on the subway in the picture taken, by passenger Noah Zerkin who posted it on Twitter yesterday.
Mr Zerkin describes himself as a “wearable computing and augmented reality enthusiast/hardware prototyper,” but told Twitter that he had got into the same subway carriage as Brin by coincidence. He said he had “a brief conversation with the most powerful man in the world. On the downtown 3 train. Nice guy.”
According to technologists, Google Glasses could allow humans to interact with their surroundings in a much more dynamic and instantaneous way. Like the company's Android software, the technology is expected to be made available to developers - possibly later this year.
Whether they will be any use on the London Underground is in question though - most stations and trains still cannot receive a signal, no matter how fancy the device.
Brin, a Moscow-born computer scientist, co-founded Google with Larry Page in 1998. He is now estimated to have a personal fortune of more than $20bn. - The Independent