The 39-year-old executive was photographed on the New York subway taking the hi-tech eyewear for a test run, The Telegraph reports.
The picture was taken by a fellow augmented reality developer named Noah Zerkin, who insists the meeting was a purely chance encounter.
"Come to think of it, perhaps I should've mentioned my projects to Mr Brin. Or given him my card," said Zerkin in hindsight.
Google unveiled the Android-powered glasses last summer, showcasing a prototype mode with video and audio capabilities as well as a built-in accelerometer.
Brin was previously seen sporting the specs at a charity event in April last year, while Google CEO Larry Page donned them for an event in London.
Google Glass is unlikely to be available to the general public until 2014, but select developers are expected to get their hands on early models this year.