Are YOU being secretly recorded? After Bill Nighy falls victim to Meta's glasses, here's how to tell if someone is wearing them

If a stranger started filming you in a café, you'd probably expect to see a smartphone pointed in your direction.

But thanks to a new generation of AI-powered smart glasses, recording someone can be as simple as wearing an ordinary-looking pair of Ray-Bans.

The technology was thrust into the spotlight this week after actor Bill Nighy was secretly filmed by a YouTube prankster wearing Ray-Ban Meta smart glasses.

A source close to the Love Actually actor described the encounter as 'very unpleasant and disrespectful'.

So how can you tell if the person sitting opposite you is wearing camera-equipped glasses, and more importantly, whether they are recording?

It turns out there are several key clues to look out for.

Experts have revealed there are several ways to tell if someone is wearing smart glasses. Pictured: Meta CEO Mark Zuckerberg wears the Meta Ray-Ban Display glasses

Look for the camera lenses

Will Greenwald, a writer covering consumer electronics at PCMag, says the biggest giveaway is often hidden in plain sight.

He notes that camera-equipped models such as Meta's Ray-Ban glasses typically feature tiny lenses built into the corners of the frame.

The camera usually appears as a small, dark circular dot embedded near the outer edge of the frame, close to the hinge.

At first glance it can look like a decorative rivet or screw rather than a camera lens. But once you know where to look, the small circular lenses can be surprisingly easy to spot.

'The technology inside is so small and discreet that they look and feel almost exactly like regular glasses,' Mr Greenwald said.

'There is a giveaway, though, and once you learn how to spot it, you'll wonder how you didn't see it before.'

Smart glasses tend to have chunky arms to contain all their hardware. They also typically feature tiny camera lenses built into the corner of the frame. Pictured: The Duchess of Edinburgh trying on Ray-Ban Meta glasses

Check how thick the arms are

Many smart glasses need room for batteries, speakers, antennas and processors.

Buyer guides and smart-glasses specialists say unusually chunky temples, seams, speaker grilles or clusters of tiny holes around the arms can all be clues that the glasses contain electronics.

Unlike traditional spectacles, smart glasses often have noticeably thicker arms to accommodate hardware hidden inside the frame.

Listen for voice commands

Many smart glasses can be activated hands-free.

Users can start recording by saying phrases such as 'Hey Meta, take a video', meaning they never need to reach for a phone or camera.

Some experts advise paying attention to brief voice prompts, unusual pauses in conversation or wearers apparently talking quietly to themselves. Repeated taps on the frame can also indicate that someone is interacting with the device.

At first glance the camera can look like a decorative rivet or screw rather than a camera lens. But once you know where to look, the small circular lenses can be surprisingly easy to spot. Pictured: Meta Ray-Ban Display AI glasses

Watch where they are looking

Because the camera generally points wherever the wearer is facing, body language can offer clues.

Technology commentators say people filming with smart glasses may make deliberate head turns, hold their gaze on particular subjects, or tilt their head slightly to frame a shot.

If someone seems unusually focused on a particular person or repeatedly turns their head to keep them in view, they may be capturing footage.

'Behaviour matters - watch for repeated temple taps, short voice prompts, and 'pause-to-read' patterns,' Even Realities, a company that manufactures AI smart glasses, said.

Look for the indicator light

The most reliable sign that recording is taking place is a small LED indicator light.

Meta's Ray-Ban glasses include a white LED on the front of the frame that illuminates when the camera is taking photos or recording video.

'Look for the small white LED on the outer right-hand side of the frame, next to the camera. Meta calls it the Capture LED. It lights when the camera is active,' experts at Tech Buzz said.

However, they warned the light can be easy to miss in bright daylight or at a distance.

A spokeswoman for Meta said: 'People use our AI glasses because they’re genuinely helpful in everyday moments like listening to music, getting live translation while traveling, or making a call hands-free. 

'They were built to be noticed, which is why every pair with a camera has a bright light on the front that blinks when you take a photo or video. 

'It cannot be turned off and the camera is disabled if someone covers or tampers with it. We will keep strengthening our protections as our glasses become even more capable.'