McIlroy was competing in a practice round alongside Ryder Cup teammate Shane Lowry on Tuesday when he was filmed approaching a patron.
The Northern Irishman asks the spectator, ‘Let me see your phone’ – and proceeds to take it before walking off.
The social media user who posted the video claims McIlroy hit a wayward tee shot into a water hazard and the fan shouted ‘just like 2011 at Augusta’ before the incident occurred.
It has not been confirmed by official sources what happened before or after the 16-second clip – and what became of the phone remains unknown.
The fan was seemingly taken aback by McIlroy’s actions, freezing with his hand outstretched and a bewildered look on his face.