A crazy bug discovered by Apple device users on Monday lets FaceTime callers listen in on the person they're calling before they answer the call. 

Videos demonstrating the flaw rocketed around social media, and my iPhone-owning colleagues have also confirmed the problem. 

It's not quite as simple as calling a friend and listening, though.

To trigger the bug, you need to first call the person you want to listen in on. While it's ringing, then create a group FaceTime call, putting in your phone number when it asks for the number of another person. The phone of the person you were calling initially will then pick up, whether they want to or not, allowing for some pretty disturbing eavesdropping if that person isn't paying attention to their phone.

Check out this demonstration shared on Twitter:

I reached out to Apple and a spokesperson there said: "We're aware of this issue and we have identified a fix that will be released in a software update later this week." 

Meanwhile, if you're concerned about someone exploiting this bug to listen in on you, you'll want to keep a close eye on your phone for incoming FaceTime calls.

Alternatively, you can deactivate FaceTime until Apple releases the promised fix by simply toggling it to off in your device settings.